SHORT-RUN SUBSIDIES AND LONG-RUN ADOPTION OF NEW HEALTH PRODUCTS: EVIDENCE FROM A FIELD EXPERIMENT

Selection and behavioral responses of health insurance subsidies in the long run: Evidence from a field experiment in Ghana

We study the effects of a health insurance subsidy in Ghana, where mandates are not enforceable. We randomly provide different levels of subsidy (1/3, 2/3, and full) and evaluate the impact at 7 months and 3 years after the intervention. We find that a one-time subsidy increased insurance enrollment for all groups in both the short and long runs, but health care utilization in the long run increased only for the partial subsidy group. We find supportive evidence that ex-post behavioral responses rather than ex-ante selective enrollment explain the long-run health care utilization results.

Effectiveness of health education interventions to improve malaria knowledge and insecticide-treated nets usage among populations of sub-Saharan Africa: systematic review and meta-analysis

Introduction

Malaria health education intervention is a community-directed approach that has long been considered important in preventing malaria in sub-Saharan Africa. However, its effectiveness is being questioned due to a lack of strong evidence. We aim to synthesize the evidence of the impact of health education on malaria knowledge and insecticide-treated nets (ITN) usage. Specifically, we analyzed the odds of correctly answering malaria-related questions and the odds of using ITN between the intervention and control groups.

Methods

Experimental and observational studies conducted in sub-Saharan Africa between 2000 and 2021 which had quantitatively evaluated the impact of health education interventions on malaria knowledge and ITN usage were included in the review.

Results

A total of 11 studies (20,523 participants) were included. Four studies used educational interventions to teach appropriate ITN strategies and promote ITN usage. Two others focused on improving knowledge of malaria transmission, prevention, treatment, and its signs and symptoms. The remaining five studies assessed both ITN use and malaria knowledge. Of these, 10 were eligible for meta-analysis. On average, the odds of a person in the intervention group reporting better malaria knowledge (odds ratio 1.30, 95% CI: 1.00 to 1.70, p = 0.05) and higher ITN usage (odds ratio 1.53, 95% CI: 1.02 to 2.29, p = 0.004) increased significantly after receiving health education interventions compared to those in the control group. The odds of ITN usage also substantially increased when the interventions were based on a theory or model (odds ratio 5.27, 95% CI: 3.24 to 8.58, p = 0.05).

Discussion

Our review highlights sub-Saharan Africa's various health education strategies to curb malaria over the past two decades. Meta-analysis findings show that health education interventions are moderately effective in improving malaria knowledge and ITN usage and have contributed to the effort of global malaria strategy.

How do malaria testing and treatment subsidies affect drug shop client expenditures? A cross-sectional analysis in Western Kenya

OBJECTIVES

To examine how drug shop clients' expenditures are affected by subsidies for malaria diagnostic testing and for malaria treatment, and also to examine how expenditures vary by clients' malaria test result and by the number of medications they purchased.

DESIGN

Secondary cross-sectional analysis of survey responses from a randomised controlled trial.

SETTING

The study was conducted in twelve private drug shops in Western Kenya.

PARTICIPANTS

We surveyed 836 clients who visited the drug shops between March 2018 and October 2019 for a malaria-like illness. This included children >1 year of age if they were physically present and accompanied by a parent or legal guardian.

INTERVENTIONS

Subsidies for malaria diagnostic testing and for malaria treatment (conditional on a positive malaria test result).

PRIMARY AND SECONDARY OUTCOME MEASURES

Expenditures at the drug shop in Kenya shillings (Ksh).

RESULTS

Clients who were randomised to a 50% subsidy for malaria rapid diagnostic tests (RDTs) spent approximately Ksh23 less than those who were randomised to no RDT subsidy (95% CI (-34.6 to -10.7), p=0.002), which corresponds approximately to the value of the subsidy (Ksh20). However, clients randomised to receive free treatment (artemisinin combination therapies (ACTs)) if they tested positive for malaria had similar spending levels as those randomised to a 67% ACT subsidy conditional on a positive test. Expenditures were also similar by test result, however, those who tested positive for malaria bought more medications than those who tested negative for malaria while spending approximately Ksh15 less per medication (95% CI (-34.7 to 3.6), p=0.102).

CONCLUSIONS

Our results suggest that subsidies for diagnostic health products may result in larger household savings than subsidies on curative health products. A better understanding of how people adjust their behaviours and expenditures in response to subsidies could improve the design and implementation of subsidies for health products.

TRIAL REGISTRATION NUMBER

NCT03810014.

Experience and confidence in health technologies: evidence from malaria testing and treatment in Western Kenya

Background

Low adoption of effective health technologies increases illness morbidity and mortality worldwide. In the case of malaria, effective tools such as malaria rapid diagnostic tests (RDTs) and artemisinin-combination therapies (ACTs) are both under-used and used inappropriately. Individuals’ confidence in RDTs and ACTs likely affects the uptake of these tools.

Methods

In a cohort of 36 households (280 individuals) in Western Kenya observed for 30 months starting in June 2017, we examined if experience with RDTs and ACTs changes people’s beliefs about these technologies and how those beliefs affect treatment behavior. Household members requested a free RDT from the study team any time they suspected a malaria illness, and positive RDT results were treated with a free ACT. We conducted annual, monthly, and sick visit surveys to elicit beliefs about the accuracy of malaria RDT results and the effectiveness of ACTs. Beliefs were elicited on a 5-point Likert scale from “very unlikely” to “very likely.”

Results

Over the study period, the percentage of survey respondents that said a hypothetical negative RDT result was “very likely” to be correct increased from approximately 55% to 75%. Controlling for initial beliefs, people who had been tested at least once with an RDT in the past year had 3.6 times higher odds (95% CI [1 1.718 7.679], P = 0.001) of saying a negative RDT was “very likely” to be correct. Confidence in testing was associated with treatment behavior: those who believed a negative RDT was “very likely” to be correct had 1.78 times higher odds (95% CI [1.079 2.934], P = 0.024) of adhering to a negative RDT result (by not taking ACTs) than those who were less certain about the accuracy of negative RDTs. Adherence to a negative test also affected subsequent beliefs: controlling for prior beliefs, those who had adhered to their previous test result had approximately twice the odds (OR = 2.19, 95% CI [1.661 2.904], P < 0.001) of saying that a hypothetical negative RDT was “very likely” to be correct compared to those who had not adhered.

Conclusions

Our results suggest that greater experience with RDTs can not only increase people’s confidence in their accuracy but also improve adherence to the test result.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14102-y.

Cash transfers as a response to COVID-19: Experimental evidence from Kenya

We deliver one month's average profit to a randomly selected group of female microenterprise owners in Dandora, Kenya, arriving just in advance of an exponential growth in COVID-19 cases. Relative to a control group, firms recoup about one third of their initial decline in profit, and food expenditures increase. Control profit responds to economic conditions and government announcements during our study period, and treatment effects are largest when control profit is at its lowest. PPE spending and precautionary management practices increase to mitigate the health risks of more intensive firm operation, but only among those who perceive COVID-19 as a major risk.

Long-lasting effects of incentives and social preference: A public goods experiment

This paper addresses the question of the effectiveness and permanence of temporary incentives to contribute to a public good. Using a common experimental framework, we investigate the effects of a recommendation that takes the form of an exhortative message to contribute, a monetary punishment and a non-monetary reward to sustain high levels of contributions. In particular, we shed light on the differential impact these mechanisms have on heterogeneous types of agents. The results show that all three incentives increase contributions compared to a pre-phase where there is no incentive. Monetary sanctions lead to the highest contributions, but a sudden drop in contributions is observed once the incentive to punish is removed. On the contrary, Recommendation leads to the lowest contributions but maintains a long-lasting impact in the Post-policy phase. In particular, it makes free-riders increase their contribution over time in the post-incentive phase. Finally, non-monetary reward backfires against those who are weakly conditional cooperators. Our findings emphasize the importance of designing and maintaining incentives not only for free-riders, but for strong and weak conditional cooperators as well, depending on characteristics of the incentives.

Can Simple Psychological Interventions Increase Preventive Health Investment?

Behavioral constraints may explain part of the low demand for preventive health products. We test the effects of two light-touch psychological interventions on water chlorination and related health and economic outcomes using a randomized controlled trial among 3,750 women in rural Kenya. One intervention encourages participants to visualize alternative realizations of the future, and the other builds participants' ability to make concrete plans. After 12 weeks, visualization increases objectively measured chlorination, reduces diarrhea episodes among children, and increases savings. Effects on chlorination and savings persist after almost 3 years. Effects of the planning intervention are weaker and largely insignificant. Analysis of mechanisms suggests both interventions increase self-efficacy-beliefs about one's ability to achieve desired outcomes. Visualization also increases participants' skill in forecasting their future utility. The interventions do not differentially affect beliefs and knowledge about chlorination. Results suggest simple psychological interventions can increase future-oriented behaviors, including use of preventive health technologies.

Non-monetary incentives for tobacco prevention among youth in Indonesia

We provide evidence on the effectiveness of a school-based program that uses a non-monetary penalty and regular monitoring to prevent risky behavior among adolescents in Indonesia. The field experiment invited students to sign a pledge to abstain from tobacco use and a similar pledge for parents to monitor their children. To test group incentives, a subset of treated schools also competed against each other for the highest tobacco abstinence rates. We find that the individual pledge increases biochemically verified tobacco abstinence by 5 percentage points. This effect is sustained 3 months after the program ended. School competition has no additional impact on tobacco abstinence. Our findings highlight the effectiveness of non-monetary incentives to curb risky behaviors among adolescents who face limited self-control and peer pressure.

Willingness to take COVID-19 vaccination in low-income countries: Evidence from Ethiopia

Background

In low-income countries, vaccination campaigns are lagging, and evidence on vaccine acceptance, a crucial public health planning input, remains scant. This is the first study that reports willingness to take COVID-19 vaccines and its socio-demographic correlates in Ethiopia, Africa’s second most populous country.

Methods

The analysis is based on a nationally representative survey data of 2,317 households conducted in the informal economy in November 2020. It employs two logistic regression models where the two outcome variables are (i) a household head’s willingness to take a COVID-19 vaccine or not, and (ii) if yes if they would also hypothetically pay (an unspecified amount) for it or not. Predictors include age, gender, education, marital status, income category, health insurance coverage, sickness due to COVID-19, chronic illness, trust in government, prior participation in voluntary activities, urban residence.

Results

Willingness to take the vaccine was high (88%) and significantly associated with COVID-19 cases in the family, trust in government and pro-social behavior. All other predictors such as gender, education, income, health insurance, chronic illness, urban residence did not significantly predict vaccine willingness at the 5% level. Among those willing to take the vaccine, 33% also answered that they would hypothetically pay (an unspecified amount) for it, an answer that is significantly associated with trust in government, health insurance coverage and income.

Conclusion

The results highlight both opportunities and challenges. There is little evidence of vaccine hesitancy in Ethiopia among household heads operating in the informal economy. The role played by trust in government and pro-social behavior in motivating this outcome suggests that policy makers need to consider these factors in the planning of COVID-19 vaccine campaigns in order to foster vaccine uptake. At the same time, as the willingness to hypothetically pay for a COVID-19 vaccine seems to be small, fairly-priced vaccines along with financial support are also needed to ensure further uptake of COVID-19 vaccines.

Mosquito-borne disease and newborn health

While mosquito-borne diseases are currently most prevalent in mid-latitude countries, rising global temperatures could expand their range. This paper investigates whether one such disease, dengue, harms newborns. The empirical design exploits epidemiological patterns of the disease spreading. Dengue infection rates in the mother's municipality of residence which prevailed during the gestation period are instrumented with exogenous factors that determine dengue incidence in municipalities that have tight social connections to the maternal municipality. Using a large longitudinal dataset of Brazilian birth records, I find that a higher dengue rate during the third trimester of gestation has a detrimental effect on birth weight. In utero exposure to dengue also increases the probability of cesarean delivery and can lead to more serious consequences such as increased fetal and maternal mortality rates.

Persistent effects of temporary incentives: Evidence from a nationwide health insurance experiment

Temporary incentives are offered in anticipation of persistent effects that are seldom estimated. We use a nationwide randomized experiment in the Philippines to estimate effects of two incentives for health insurance three years after their withdrawal. We find that both temporary incentives had persistent effects on enrollment. A premium subsidy had a small but highly persistent effect. Application assistance offered to those initially unresponsive to the subsidy had a much larger but less persistent effect. The subsidy persuaded those with higher initial stated willingness to pay to enroll and keep enrolling. The offer of application assistance to initial non-compliers with the subsidy achieved a larger immediate effect by drawing in those who stated they valued insurance less and were less likely to re-enroll when the incentives were withdrawn.

Demand for Information on Environmental Health Risk, Mode of Delivery, and Behavioral Change: Evidence from Sonargaon, Bangladesh

Millions of villagers in Bangladesh are exposed to arsenic by drinking contaminated water from private wells. Testing for arsenic can encourage switching from unsafe wells to safer sources. This study describes results from a cluster randomized controlled trial conducted in 112 villages in Bangladesh to evaluate the effectiveness of different test selling schemes at inducing switching from unsafe wells. At a price of about US0.60, only one in four households purchased a test. Sales were not increased by informal inter-household agreements to share water from wells found to be safe, or by visual reminders of well status in the form of metal placards mounted on the well pump. However, switching away from unsafe wells almost doubled in response to agreements or placards relative to the one in three proportion of households that switched away from an unsafe well with simple individual sales.

Demand for Information on Environmental Health Risk, Mode of Delivery, and Behavioral Change: Evidence from Sonargaon, Bangladesh

Millions of villagers in Bangladesh are exposed to arsenic by drinking contaminated water from private wells. Testing for arsenic can encourage switching from unsafe wells to safer sources. This study describes results from a cluster randomized controlled trial conducted in 112 villages in Bangladesh to evaluate the effectiveness of different test selling schemes at inducing switching from unsafe wells. At a price of about US0.60, only one in four households purchased a test. Sales were not increased by informal inter-household agreements to share water from wells found to be safe, or by visual reminders of well status in the form of metal placards mounted on the well pump. However, switching away from unsafe wells almost doubled in response to agreements or placards relative to the one in three proportion of households that switched away from an unsafe well with simple individual sales.

Effects of Vision Health Education and Free Eyeglasses on Knowledge of Vision and Usage of Spectacles Among Primary School Students: Evidence from Gansu and Shaanxi Provinces in China

Background

In rural China, children’s vision problems are very common, with many who would benefit from refractive correction not getting the care they need. This study examines whether a health information campaign that involves vision health education and a free trial of health product with free eyeglasses is effective at raising students’ awareness of myopia and promoting students’ eyeglasses usage.

Methods

We conducted an in-the-field randomized controlled experiment of a program providing vision health education and subsidized free eyeglasses to myopic children from 168 primary schools in rural Northwestern China in 2012.

Results

A total of 2189 students, mean age 10.5 years (49.3% male), participated in the baseline survey. At the baseline, the average correct response rate for visual knowledge among the sample students was 30.1%, and only 15% who needed eyeglasses used them. Seven months after intervention, the average correct response rate for vision knowledge were 48.5% and 48.3% in the education group and the education plus free eyeglasses group respectively, significantly higher than that of the control group. The rate of eyeglasses usage was 36% and 43% in the free eyeglasses group and the education plus free eyeglasses group respectively, significantly higher than that of the control group. The rate of eyeglasses compliance in the free eyeglasses group and the education plus free eyeglasses group was 19% and 26%, which also were significantly higher than the control group.

Conclusion

The information campaign combined with subsidized eyeglasses had a better effect both on vision knowledge and eyeglasses usage. The information campaign improved knowledge by providing the right information, and free eyeglasses changed the perceived utility and experience by the students using the product and getting benefits. Information and the free eyeglasses (subsidized) are complements.

Free Access to a Broad Contraceptive Method Mix and Women's Contraceptive Choice: Evidence from Sub-Saharan Africa

Financial barriers may restrict women's ability to use their preferred contraceptive methods, especially long-acting reversible contraceptives (LARC). Providing free access to a broad contraceptive method mix, including both LARC and short-acting reversible contraceptives (SARC), may increase contraceptive use, meet women's various fertility needs, and increase their agency in contraceptive decisions. Linking facility and individual data from eight countries in sub-Saharan Africa, we use a propensity score approach combined with machine learning techniques to examine how free access to a broad contraceptive method mix affects women's contraceptive choice. Free access to both LARC and SARC was associated with an increase of 3.2 percentage points (95 percent confidence interval: 0.006, 0.058) in the likelihood of contraceptive use, driven by greater use of SARC. Among contraceptive users, free access did not prompt women to switch to LARC and had no effect on contraceptive decision-making. The price effects were larger among older and more educated women, but free access was associated with lower contraceptive use among adolescents. While free access to contraceptives is associated with a modest increase in contraceptive use for some women, removing user fees alone does not address all barriers women face, especially for the most vulnerable groups of women.

Improving the adoption of household health products: A sales experiment with chlorine tablets

We test a door-to-door marketing intervention aimed to increase use of a targeted health product among poor households. Specifically, we examine three treatments in which this good-chlorine tablets for drinking water purification-is: (1) sold alone, (2) sold alongside a familiar and cheaper side good that is priced at its retail value, and (3) sold alongside the same side good that is priced on a promotional offer. The side good when sold at retail price is intended to be an "opt-out" good to reduce the marketing pressure, which should in turn reduce the amount of products sold that go unused. When the side good is sold on promotion, however, we hypothesize that it reintroduces marketing pressure due to the "gift" aspect of the promotion. Consistent with this hypothesis, we find that chlorine use is nearly double in the second condition compared to the other two conditions. Our results suggest that household valuation of a new product is shaped by both the presence and the price of a side good due to marketing pressure.

When less is more: Can reduced health monitoring improve medication adherence?

As the prevalence of chronic diseases rises, improving self-management has become an important determinant of the productivity of healthcare delivery. Recently, Mexico's largest healthcare provider began issuing automatic-refill prescriptions to stable hypertensive patients, thus reducing the frequency of health monitoring from 30- to 90-day intervals. Exploiting this change, I find that less monitoring implies no drawbacks in health outcomes and actually improves self-management of disease by increasing medication adherence when baseline monitoring is relatively frequent. The number of days when patients are out of medication between fillings falls by 2.2 days-an improvement in adherence of 6.4%. Furthermore, patients appear to value being on a low-frequency regime as they improve adherence in order to remain on it, suggesting that lower monitoring could be used as a "reward" to promote medication adherence or, potentially, other health behaviors. Finally, I find evidence of positive spillovers on adherence, as clinic congestion falls.

What Can Children Learn from a Free Trial of Eyeglasses Use? Evidence from a Cluster‑Randomized Controlled Trial in Rural China

Free trial is a widely used business strategy that takes advantage of information asymmetry. However, evidence on what we can learn and how rapidly we can learn from a free trial of health care is limited. This study evaluates the effect of a free trial of eyeglasses on children's 8 items of perception related to eyeglasses use. An evaluation was conducted alongside a cluster-randomized controlled trial involved 832 myopic children from northwest rural China. A total of 428 myopic children from 42 schools were randomized to receive free eyeglasses, and 404 myopic children from 42 schools were randomized as control group. We find that the perceived costs and benefits of eyeglasses use and the perceived timing of wearing eyeglasses at the appropriate time can be learned from a free trial of eyeglasses. Compared with the control group in the long run, 5.6 percentage points more children in treatment group agreed that wearing eyeglasses was attractive, 16.5 percentage points more children agreed that wearing eyeglasses is helpful to academic performance, and 7.9 percentage points more children agreed that children with vision problems should wear eyeglasses. Due to the effects of a free product and the time to learning from experience, the magnitude of the impact of a free trial changed over time. We also find that the indirect experience, such as a vision protection course, cannot change children' perceptions about the cost or benefits of eyeglasses use. The findings imply that children can learn significantly from the experience of a free trial of eyeglasses. A free trial is an effective strategy to solve the information asymmetry problem for health care. The first pair of eyeglasses of children can be one-off subsidized to trigger demand for eyeglasses use.

Managing the spread of disease with mobile phone data

While human mobility has important benefits for economic growth, it can generate negative externalities. This paper studies the effect of mobility on the spread of disease in a low-incidence setting when people do not internalize their risks to others. Using malaria as a case study and 15 billion mobile phone records across nine million SIM cards, this paper quantifies the relationship between travel and the spread of disease. The estimates indicate that an infected traveler contributes to 1.66 additional cases reported in the health facility at the traveler's destination. This paper develops a simulation-based policy tool that uses mobile phone data to inform strategic targeting of travelers based on their origins and destinations. The simulations suggest that targeting informed by mobile phone data could reduce the caseload by 50 percent more than current strategies that rely only on previous incidence.

Private health investments under competing risks: Evidence from malaria control in Senegal

This study exploits the introduction of high subsidies for anti-malaria products in Senegal in 2009 to investigate whether malaria prevents parents from investing in child health. A simple model of health investments under competing mortality risks predicts that private expenses to fight malaria and other diseases should increase in response to anti-malaria public interventions. We test and validate this prediction using original panel data from a household expenditure survey combined with geographical information on malaria prevalence. We find that health expenditures in malarious regions catch up with non-malarious regions. The same result holds for parental health-seeking behavior against other diseases like diarrhea. These patterns cannot be explained by differential trends between regions. Our results suggest that behavioral responses to anti-malaria campaigns magnify their impact on all-cause mortality for children.

Does improving appropriate use of malaria medicines change population beliefs in testing and treatment? Evidence from a randomized controlled trial

A major puzzle in malaria treatment remains the dual problem of underuse and overuse of malaria medications, which deplete scarce public resources used for subsidies and lead to drug resistance. One explanation is that health behaviour, especially in the context of incomplete information, could be driven by beliefs, pivotal to the success of health interventions. The objective of this study is to investigate how population beliefs change in response to an experimental intervention which was shown to improve access to rapid diagnostic testing (RDT) through community health workers (CHWs) and to increase appropriate use of anti-malaria medications. By collecting data on individuals' beliefs on malaria testing and treatment 12 and 18 months after the experimental intervention started, we find that the intervention increases the belief that a negative test result is correct, and the belief that the first-line anti-malaria drugs (artemisinin-based combination therapies or ACTs) are effective. Using mediation analysis, we also explore some possible mechanisms through which the changes happen. We find that the experience and knowledge about RDT and experience with CHWs explain 62.4% of the relationship between the intervention and the belief that a negative test result is correct. Similarly, the targeted use of ACTs and taking the correct dose-in addition to experience with RDT-explain 96.8% of the relationship between the intervention and the belief that the ACT taken is effective. As beliefs are important determinants of economic behaviour and might guide individuals' future decisions, understanding how they change after a health intervention has important implications for long-term changes in population behaviour.

Understanding the role of disease knowledge and risk perception in shaping preventive behavior for selected vector-borne diseases in Guyana

BACKGROUND

Individual behavior, particularly choices about prevention, plays a key role in infection transmission of vector-borne diseases (VBDs). Since the actual risk of infection is often uncertain, individual behavior is influenced by the perceived risk. A low risk perception is likely to diminish the use of preventive measures (behavior). If risk perception is a good indicator of the actual risk, then it has important implications in a context of disease elimination. However, more research is needed to improve our understanding of the role of human behavior in disease transmission. The objective of this study is to explore whether preventive behavior is responsive to risk perception, taking into account the links with disease knowledge and controlling for individuals' socioeconomic and demographic characteristics. More specifically, the study focuses on malaria, dengue fever, Zika and cutaneous leishmaniasis (CL), using primary data collected in Guyana-a key country for the control and/or elimination of VBDs, given its geographic location.

METHODS AND FINDINGS

The data were collected between August and December 2017 in four regions of the country. Questions on disease knowledge, risk perception and self-reported use of preventive measures were asked to each participant for the four diseases. A structural equation model was estimated. It focused on data collected from private households only in order to control for individuals' socioeconomic and demographic characteristics, which led to a sample size of 497 participants. The findings showed evidence of a bidirectional association between risk perception and behavior. A one-unit increase in risk perception translated into a 0.53 unit increase in self-reported preventive behavior for all diseases, while a one-unit increase in self-reported preventive behavior (i.e. the use of an additional measure) led to a 0.46 unit decrease in risk perception for all diseases (except CL). This study also showed that higher education significantly improves knowledge and that better knowledge increases the take up of preventive measures for malaria and dengue, without affecting risk perception.

CONCLUSIONS

In trying to reach elimination, it appears crucial to promote awareness of the risks and facilitate access to preventive measures, so that lower risk perception does not translate into lower preventive behavior.

Does a Free-Trial Approach Increase Purchase and Use of a Household Water Treatment and Safe Storage Product in Rural Haiti?

A cluster, randomized control trial was conducted to assess the effects of social marketing approach on purchase rates and water treatment behavior of Klorfasil, a chlorine-based household water treatment product among seven villages in Thomassique, Haiti, from May to December 2016. Villages were randomized to the free-trial (257 households) or cost-sharing (240 households) group. Households in the free-trial group were allowed 30 days of free Klorfasil use before purchase decision. Households who purchased Klorfasil were then followed up for 30, 60, and 180 days. At the last follow-up, respondents were asked if they would like to repurchase Klorfasil. Questionnaire survey and water quality assessment by residual-free chlorine were conducted in each survey. Chi-square test, t-test, and logistic regression were applied. The first purchase rate of the cost-sharing group was significantly higher than that of the free-trial group (79.2% versus 67.3%). By contrast, the repurchase rate of the free-trial group was higher (82.9% versus 66.3%). However, the overall repurchase rate was 71.6% and the proportion of long-term users was significantly higher in the cost-sharing group (56% versus 47%). Water treatment rates in the cost-sharing group were significantly higher than those in the free-trial group in the first and final surveys (odds ratio [OR] = 0.15, OR = 0.32). Households with high and medium economic status both had significantly higher purchase rates than low economic status households (OR = 4.40, OR = 1.94). Households with higher educated respondents had significantly better water treatment practices (OR = 2.15). The free-trial approach did not increase the first purchase rate but increased the repurchase rate later. The cost-sharing approach significantly encouraged long-term usage.

Short- & long-term effects of monetary and non-monetary incentives to cooperate in public good games: An experiment

Using a common experimental framework, this paper addresses both the question of the short-term and the long-lasting effects of temporary monetary and non-monetary incentive mechanisms on increasing individual contributions to the public good. The results show that both punishments and rewards significantly increase contributions compared to the baseline, but that monetary sanctions lead to the highest contributions, whereas non-monetary sanctions lead to the lowest contributions. The four types of incentives display long-lasting effects, i.e., contributions do not go back to baseline levels directly after the withdrawal of the incentives. However, rewards appear to have much stronger persistent effects than sanctions, revealing some sort of delayed reciprocity.

Willingness-to-pay for long-lasting insecticide-treated bed nets: a discrete choice experiment with real payment in Ghana

Background

Expanding access to long-lasting insecticidal nets (LLINs) is difficult if one is limited to government and donor financial resources. Private commercial markets could play a larger role in the continuous distribution of LLINs by offering differentiated LLINs to middle-class Ghanaians. This population segment has disposable income and may be willing to pay for LLINs that meet their preferences. Measuring the willingness-to-pay (WTP) for LLINs with specialty features that appeal to middle-class Ghanaians could help malaria control programmes understand what is the potential for private markets to work alongside fully subsidized LLIN distribution channels to assist in spreading this commodity.

Methods

This study conducted a discrete choice experiment (DCE) including a real payment choice among a representative sample of 628 middle-income households living in Ashanti, Greater Accra, and Western regions in Ghana. The DCE presented 18 paired combinations of LLIN features and various prices. Respondents indicated which LLIN of each pair they preferred and whether they would purchase it. To validate stated willingness-to-pay, each participant was given a cash payment of $14.30 (GHS 65) that they could either keep or immediately spend on one of the LLIN products.

Results

The households’ average probability of purchasing a LLIN with specialty features was 43.8% (S.D. 0.07) and WTP was $7.48 (GHS34.0). The preferred LLIN features were conical or rectangular one-point-hang shape, queen size, and zipper entry. The average WTP for a LLIN with all the preferred features was $18.48 (GHS 84). In a scenario with the private LLIN market, the public sector outlay could be reduced by 39% and private LLIN sales would generate $8.1 million ($311 per every 100 households) in revenue in the study area that would support jobs for Ghanaian retailers, distributors, and importers of LLINs.

Conclusion

Results support a scenario in which commercial markets for LLINs could play a significant role in improving access to LLINs for middle-income Ghanaians. Manufacturers interested could offer LLIN designs with features that are most highly valued among middle-income households in Ghana and maintain a retail price that could yield sufficient economic returns.

Assessing the Demand for Plastic Latrine Slabs in Rural Kenya

Improving access to safe and affordable sanitation facilities is a global health priority that is essential for meeting the United Nation's Sustainable Development Goals. To promote the use of improved sanitation in rural and low-income settings, plastic latrine slabs provide a simple option for upgrading traditional pit latrines. The International Finance Corporation/World Bank Selling Sanitation program estimated that plastic slabs would have a 34% annual growth, with a market size of US$2.53 million in Kenya by 2017. In this study, we examined the commercial viability of these plastic latrine slabs in rural Kenya by evaluating a financing and distribution model intervention, documenting household slab sales to date, and assessing consumer exposure and perceptions. We also determined household willingness to pay through a real-money auction with 322 households. We found that no households in our study area had purchased the plastic slabs. The primary barriers to slab sales were limited marketing activities and low demand compared with the sales price: households were willing to pay an average of US$5 compared with a market price of US$16. Therefore, current household demand for the plastic latrine slabs in rural Kenya is too low to support commercial distribution. Further efforts are required to align the price of plastic latrine slabs with consumer demand in this setting, such as additional demand creation, product financing, and public sector investment.

Effect of Prices, Distribution Strategies, and Marketing on Demand for HIV Self-testing in Zimbabwe: A Randomized Clinical Trial

IMPORTANCE

HIV self-testing is a promising approach for increasing awareness of HIV status in sub-Saharan Africa, particularly in Zimbabwe, where HIV prevalence is 13%. Evidence is lacking, however, on the optimal pricing policies and delivery strategies for maximizing the effect of HIV self-testing.

OBJECTIVE

To assess demand for HIV self-testing among adults and priority-population subgroups under alternative pricing and distribution strategies.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial recruited study participants between February 15, 2018, and April 25, 2018, in urban and rural communities in Zimbabwe. A factorial design was used to randomize participants to a combination of self-test price, distribution site, and promotional message. Individuals and their household members had to be at least 16 years old to be eligible for participation. This intention-to-treat population comprised 3996 participants.

INTERVENTIONS

Participants were given a voucher that could be redeemed for an HIV self-test within 1 month at varying prices (US $0-$3) and distribution sites (clinics or pharmacies in urban areas, and retail stores or community health workers in rural areas). Vouchers included randomly assigned promotional messages that emphasized the benefits of HIV testing.

MAIN OUTCOMES AND MEASURES

Proportion of participants who obtained self-tests in each trial arm, measured by distributor records.

RESULTS

Among the 4000 individuals enrolled, 3996 participants were included. In total, the mean (SD) age was 35 (14.7) years, and most participants (2841 [71.1%]) were female. Self-testing demand was highly price sensitive; 260 participants (32.5%) who were offered free self-tests redeemed their vouchers, compared with 55 participants (6.9%) who were offered self-tests for US $0.50 (odds ratio [OR], 0.14; 95% CI, 0.10-0.19), a reduction in demand of more than 25 percentage points. Demand was below 3% in the $1, $2, and $3 groups, which was statistically significantly lower than the demand in the free distribution group: in pooled analyses, demand was considerably lower among participants in higher-than-$0 price groups compared with the free distribution group (2.8% vs 32.5%; OR, 0.05; 95% CI, 0.04-0.07). In urban areas, demand was statistically significantly higher with pharmacy-based distribution compared with clinic-based distribution (6.8% vs 2.9%; adjusted OR, 2.78; 95% CI, 1.74-4.45). Price sensitivity was statistically significantly higher among rural residents, men, and those who had never received testing before. Promotional messages did not influence demand.

CONCLUSIONS AND RELEVANCE

This study found that demand for HIV self-testing in Zimbabwe was highly price sensitive, suggesting that free distribution may be essential for promoting testing among high-priority population groups; additionally, pharmacy-based distribution was preferable to clinic-based distribution in urban areas.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03559959.

HIV prevention among youth: A randomized controlled trial of voluntary counseling and testing for HIV and male condom distribution in rural Kenya

OBJECTIVE

Voluntary Counseling and Testing for HIV (VCT) and increasing access to male condoms are common strategies to respond to the HIV/AIDS pandemic. Using biological and behavioral outcomes, we compared programs to increase access to VCT, male condoms or both among youth in Western Kenya with the standard available HIV prevention services within this setting.

DESIGN

A four arm, unblinded randomized controlled trial.

METHODS

The sample includes 10,245 youth aged 17 to 24 randomly assigned to receive community-based VCT, 150 male condoms, both VCT and condoms, or neither program. All had access to standard HIV services available within their communities. Surveys and blood samples for HSV-2 testing were collected at baseline (2009-2010) and at follow up (2011-2013). VCT was offered to all participants at follow up. HSV-2 prevalence, the primary outcome, was assessed using weighted logistic regressions in an intention-to-treat analysis.

RESULTS

For the 7,565 respondents surveyed at follow up, (effective tracking rate = 91%), the weighted HSV-2 prevalence was similar across groups (control group = 10.8%, condoms only group = 9.1%, VCT only group = 10.2%, VCT and condoms group = 11.5%). None of the interventions significantly reduced HSV-2 prevalence; the adjusted odds ratios were 0.87 (95% CI: 0.61-1.25) for condoms only, 0.94 (95% CI: 0.64-1.38) for VCT only, and 1.12 (95% CI: 0.79-1.58) for both interventions. The VCT intervention significantly increased HIV testing (adj OR: 3.54, 95% CI: 2.32-5.41 for VCT only, and adj OR: 5.52, 95% CI: 3.90-7.81 for condoms and VCT group). There were no statistically significant effects on risk of HIV, or on other behavioral or knowledge outcomes including self-reported pregnancy rates.

CONCLUSION

This study suggests that systematic community-based VCT campaigns (in addition to VCT availability at local health clinics) and condom distribution are unlikely on their own to significantly reduce the prevalence of HSV-2 among youth.

Alcohol and Self-Control: A Field Experiment in India

This paper studies alcohol consumption among low-income workers in India. In a 3-week field experiment, the majority of 229 cycle-rickshaw drivers were willing to forgo substantial monetary payments in order to set incentives for themselves to remain sober, thus exhibiting demand for commitment to sobriety. Randomly receiving sobriety incentives significantly reduced daytime drinking while leaving overall drinking unchanged. I find no evidence of higher daytime sobriety significantly changing labor supply, productivity, or earnings. In contrast, increasing sobriety raised savings by 50 percent, an effect that does not appear to be solely explained by changes in income net of alcohol expenditures.

Subsidies for Agricultural Technology Adoption: Evidence from a Randomized Experiment with Improved Grain Storage Bags in Uganda

This article addresses the question of whether subsidizing an entirely new agricultural technology for smallholder farmers can aid its adoption early in the diffusion process. Based on a theoretical framework for technology adoption under subjective uncertainty, we implemented a randomized field experiment among 1,200 smallholders in Uganda to estimate the extent to which subsidizing an improved grain storage bag crowds-out or crowds-in commercial buying of the technology. The empirical results show that on average, subsidized households are more likely to buy an additional bag at commercial prices relative to the households with no subsidy who are equally aware of the technology. This suggests that under certain circumstances, such as when there is uncertainty about the effectiveness of a new agricultural technology, and the private sector market for the technology is weak or nascent, a one-time use of subsidy to build awareness and reduce risk can help generate demand for the new technology and thus crowd-in commercial demand for it. In this context, a subsidy can allow farmers to experiment with the technology and learn from the experience before investing in it. JEL codes: C23, C93, O33, Q12, Q18.

How does anonymous online peer communication affect prevention behavior? Evidence from a laboratory experiment

While the importance of social networks for health behaviors is well-recognized, relatively little is known regarding the accuracy of anonymous online communication and its impact on health behavior. In 2012, we conducted a laboratory experiment in Boston, Massachusetts with 679 individuals to understand how anonymous online communication affects individual prevention decisions. Participants had to opt for or against investing in prevention over three sessions, each consisting of 15 experimental rounds. In the third session only, participants could share their experiences with a group of 1-3 other anonymous participants after each round. Groups exchanged an average of 16 messages over the 15 rounds of the third session. 70% of messages contained information about the subject's prevention decision and the resulting health outcome. Participants were more likely to communicate when they prevented than when they did not, with prevention failures resulting in the highest probability of sending a message. Nonetheless, receiving an additional message reporting prevention increased the odds a subject would prevent by 32 percent. We find that participants tend to adopt the prevention behavior reported by others, with less weight given to the reported outcomes of prevention, suggesting that social networks may influence behaviors through more than just information provision.

Access to environmental health assets across wealth strata: Evidence from 41 low- and middle-income countries

INTRODUCTION

Low levels of household access to basic environmental health assets (EHAs)-including technologies such as clean cookstoves and bed nets or infrastructure such as piped water and electricity-in low- and middle-income countries (LMICs) are known to contribute significantly to the global burden of disease. This low access persists despite decades of promotion of many low-cost, life-saving technologies, and is particularly pronounced among poor households. This study aims to characterize variation in access to EHAs among LMIC households as a function of wealth, as defined by ownership of various assets.

METHODS

Demographic and Health Survey (DHS) data from 41 low- and middle-income countries were used to assess household-level access to the following EHAs: 1) improved water supply; 2) piped water supply; 3) improved sanitation; 4) modern cooking fuels; 5) electricity; and 6) bed nets. For comparison, we included access to mobile phones, which is considered a highly successful technology in terms of its penetration into poor households within LMICs. Ownership levels were compared across country-specific wealth quintiles constructed from household assets using bivariate analysis and multivariable linear regression models.

RESULTS

Access to EHAs was low among the households in the bottom three quintiles of wealth. Access to piped water, modern cooking fuels, electricity and improved sanitation, for example, were all below 50% for households in the bottom three wealth quintiles. Access to certain EHAs such as improved water supply and bed nets increased only slowly with concomitant increases in wealth, while gaps in access to other EHAs varied to a greater degree by wealth quintile. For example, disparities in access between the richest and poorest quintiles were greatest for electricity and improved sanitation. Rural households in all wealth quintiles had much lower levels of access to EHAs, except for bed nets, relative to urban households.

CONCLUSIONS

The findings of this study provide a basis for understanding how EHAs are distributed among poor households in LMICs, elucidate where inequalities in access are particularly pronounced, and point to a need for strategies that better reach the poor, if the global environmental burden of disease is to be reduced.

Household demand persistence for child micronutrient supplementation

Addressing early-life micronutrient deficiencies can improve short- and long-term outcomes. In most contexts, private supply chains will be key to effective and efficient preventative supplementation. With established vendors, we conducted a 60-week market trial for a food-based micronutrient supplement in rural Burkina Faso with randomized price and non-price treatments. Repeat purchases - critical for effective supplementation - are extremely price sensitive. Loyalty cards boost demand more than price discounts, particularly in non-poor households where the father is the cardholder. A small minority of households achieved sufficient supplementation for their children through purely retail distribution, suggesting the need for more creative public-private delivery platforms informed by insights into household demand persistence and heterogeneity.

Receptiveness to advice, cognitive ability, and technology adoption☆

We construct a model of technology adoption with agents differing on two dimensions: their cognitive ability and their receptiveness to advice. While cognitive ability unambiguously speeds adoption, receptiveness to advice may speed adoption for individuals with low cognitive ability, but slow adoption for individuals with high cognitive ability. We conduct economic experiments measuring US farmers' cognitive ability and receptiveness to advice and examine how these characteristics impact their speed of adoption of genetically modified (GM) corn seeds. The empirical analysis shows that early adopters are those who are both quite able cognitively and not receptive to advice.

The impact of a mosquito net voucher subsidy programme on incremental ownership: The case of the Tanzania National Voucher Scheme

The subsidisation of mosquito nets has been widely used to increase ownership in countries where malaria represents a public health problem. However, an important question that has not been addressed empirically is how far net subsidy programmes increase ownership above the level that would have prevailed in the absence of the subsidy (i.e., incremental ownership). This study addresses that gap by investigating the impact of a large-scale mosquito net voucher subsidy--the Tanzania National Voucher Scheme (TNVS)--on short-term demand for unsubsidised commercial nets, estimating a household demand model with nationally representative household survey data. The results suggest that, despite the TNVS using a categorical targeting approach that did not discriminate by wealth, it still led to a large increase in incremental ownership of mosquito nets, with limited evidence of displacement of unsubsidised sales. Although no evidence is found of an additional TNVS voucher decreasing the number of unsubsidised sales in the same period, results indicate that an additional TNVS voucher reduced the probability of purchasing any unsubsidised net in the same period by 14%. The findings also highlight the critical role played by social learning or campaign messaging in increasing mosquito net ownership.

Effect and cost-effectiveness of educating mothers about childhood DPT vaccination on immunisation uptake, knowledge, and perceptions in Uttar Pradesh, India: A randomised controlled trial

BACKGROUND

To assess the effect of health information on immunisation uptake in rural India, we conducted an individually randomised controlled trial of health information messages targeting the mothers of unvaccinated or incompletely vaccinated children through home visits in rural Uttar Pradesh, India.

METHODS AND FINDINGS

The study tested a brief intervention that provided mothers face-to-face with information on the benefits of the tetanus vaccine. Participants were 722 mothers of children aged 0-36 months who had not received 3 doses of diphtheria-pertussis-tetanus (DPT) vaccine (DPT3). Mothers were randomly assigned in a ratio of 1:1:1 to 1 of 3 study arms: mothers in the first treatment group received information framed as a gain (e.g., the child is less likely to get tetanus and more likely to be healthy if vaccinated), mothers in the second treatment group received information framed in terms of a loss (e.g., the child is more likely to get tetanus and suffer ill health if not vaccinated), and the third arm acted as a control group, with no information given to the mother. Surveys were conducted at baseline (September 2015) and after the intervention (April 2016). The primary outcome was the proportion of children who had received DPT3 measured after 7 months of follow-up. The analysis was by intention to treat. A total of 16 (2.2%) participants were lost to follow-up. The coverage of DPT3 was 28% in the control group and 43% in the pooled information groups, giving a risk difference of 15 percentage points (95% CI: 7% to 22%, p < 0.001) and a relative risk of 1.52 (95% CI: 1.2 to 1.9, p < 0.001). The information intervention increased the rate of measles vaccination by 22 percentage points (risk difference: 22%, 95% CI: 14% to 30%, p < 0.001; relative risk: 1.53, 95% CI: 1.29 to 1.80) and the rate of full immunisation by 14 percentage points (risk difference: 14%, 95% CI: 8% to 21%, p < 0.001; relative risk: 1.72, 95% CI: 1.29 to 2.29). It had a large positive effect on knowledge of the causes, symptoms, and prevention of tetanus but no effect on perceptions of vaccine efficacy. There was no difference in the proportion of children with DPT3 between the group that received information framed as a loss and the group that received information framed as a gain (risk difference: 4%, 95% CI: -5% to 13%; p = 0.352; relative risk: 1.11, 95% CI: 0.90 to 1.36). The cost per disability-adjusted life year averted of providing information was US$186, making the intervention highly cost-effective with respect to the WHO-recommended threshold of once the gross domestic product per capita (US$793 in the case of Uttar Pradesh). Key study limitations include the modest sample size for this trial, limiting power to detect small differences in the framing of information, and the potential for contamination among households.

CONCLUSIONS

Providing mothers of unvaccinated/incompletely vaccinated children with information on tetanus and the benefits of DPT vaccination substantially increased immunisation coverage and was highly cost-effective. The framing of the health information message did not appear to matter.

TRIAL REGISTRATION

The trial is registered with ISRCTN, number ISRCTN84560580.

The effect of price on demand for and use of bednets: evidence from a randomized experiment in Madagascar

There is an on-going debate about whether health products, such as insecticide-treated bednets (ITNs) for protection against malaria, should be distributed for free or at a positive price to maximize ownership and use. One argument in favour of free distribution is related to positive externalities. Like vaccines, individual use of ITNs provides a community-wide protective effect against malaria even for non-users. In addition, price may act as a barrier to ownership particularly among those most at-risk who are frequently poor. Alternatively, charging a positive price may reduce donor dependence, more efficiently allocate nets to those most at risk of malaria, and encourage use through a hypothesized sunk cost effect, where individuals are more likely to use goods they pay for. Using a randomized experiment in Madagascar, we evaluate the impact of price on demand for and use of ITNs. We find that price negatively affects both demand and use of ITNs. When price increases by $0.55, demand falls by 23.1% points (CI 19.6–26.6; P < 0.01) and effective coverage falls by 23.1% points (CI 19.6–26.6; P < 0.01). We fail to find evidence of a screening effect for prices greater than zero, but households eligible for free ITNs are more likely to use them if they have more self-reported fevers in the household at baseline. We also fail to find evidence of a sunk cost effect, meaning that households are not more likely to use nets that they pay for. Our results suggest that: (1) only partially subsidizing ITNs significantly limits ownership and (2) distributing ITNs for free or at a small nominal price will maximize demand and effective coverage. Alternative sources of financing should be identified to completely (or almost completely) subsidize the cost of ITNs in order to maximize coverage of ITNs among poor populations at risk of malaria.

Market for Artemether-Lumefantrine to treat childhood malaria in a district of southern Mozambique

Malaria is one of the leading causes of death in sub-Saharan Africa. Artemisinin-based combination therapies are used as first-line treatment drugs, but their market is far from competitive. Market failures include limited availability, low quality, lack of information, and high costs of access. We estimated the theoretical demand for one of the most common artemisinin-based combination therapies, artemether-lumefantrine (AL), and its determinants among caregivers of children with malaria seeking care at public health facilities, thus, entitled to receive drugs for free, in southern Mozambique (year 2012). The predicted theoretical demand was contrasted with international and local private market AL prices. Respondents stated high willingness to pay but lower ability to pay (ATP), which was defined as the theoretical demand. The ATP was on average of 0.94 USD for the treatment of a malaria episode. This implied an average gap of 1.04 USD between average local private prices and theoretical demand. Predicted ATP decreased by 14% for every additional malaria episode that the child had suffered during the malaria season. The market price was unaffordable for a large share of our sample, highlighting an unequal welfare distribution between suppliers and potential consumers, as well as issues of inequity in the private delivery of AL.

Governance and the effectiveness of public health subsidies: Evidence from Ghana, Kenya and Uganda

Distributing subsidized health products through existing health infrastructure could substantially and cost-effectively improve health in sub-Saharan Africa. There is, however, widespread concern that poor governance - in particular, limited health worker accountability - seriously undermines the effectiveness of subsidy programs. We audit targeted bednet distribution programs to quantify the extent of agency problems. We find that around 80% of the eligible receive the subsidy as intended, and up to 15% of subsidies are leaked to ineligible people. Supplementing the program with simple financial or monitoring incentives for health workers does not improve performance further and is thus not cost-effective in this context.

Tiered co-payments, pricing, and demand in reference price markets for pharmaceuticals

Health insurance companies curb price-insensitive behavior and the moral hazard of insureds by means of cost-sharing, such as tiered co-payments or reference pricing in drug markets. This paper evaluates the effect of price limits - below which drugs are exempt from co-payments - on prices and on demand. First, using a difference-in-differences estimation strategy, we find that the new policy decreases prices by 5 percent for generics and increases prices by 4 percent for brand-name drugs in the German reference price market. Second, estimating a nested-logit demand model, we show that consumers appreciate co-payment exempt drugs and calculate lower price elasticities for brand-name drugs than for generics. This explains the different price responses of brand-name and generic drugs and shows that price-related co-payment tiers are an effective tool to steer demand to low-priced drugs.

Optimizing Household Chlorination Marketing Strategies: A Randomized Controlled Trial on the Effect of Price and Promotion on Adoption in Haiti

Household water treatment can reduce diarrheal morbidity and mortality in developing countries, but adoption remains low and supply is often unreliable. To test effects of marketing strategies on consumers and suppliers, we randomized 1,798 households in rural Haiti and collected data on purchases of a household chlorination product for 4 months. Households received randomly selected prices ($0.11-$0.56 per chlorine bottle), and half received monthly visits from sales agents. Each $0.22 drop in price increased purchases by 0.10 bottles per household per month (P < 0.001). At the mean price, each 1% drop in price increased purchases by 0.45% (elasticity = 0.45). There is suggestive evidence that household visits by some sales agents increased purchases at mid-range prices; however, the additional revenue did not offset visit cost. Choosing the lowest price and conducting visits maximizes chlorine purchase, whereas slightly raising the retail price and not conducting visits maximizes cost recovery. For the equivalent cost, price discounts increase purchases 4.2 times as much as adding visits at the current retail price. In this context, price subsidies may be a more cost-effective use of resources than household visits, though all marketing strategies tested offer cost-effective ways to achieve incremental health impact. Decisions about pricing and promotion for health products in developing countries affect health impact, cost recovery, and cost-effectiveness, and tradeoffs between these goals should be made explicit in program design.

Targeting health subsidies through a nonprice mechanism: A randomized controlled trial in Kenya

Free provision of preventive health products can markedly increase access in low-income countries. A cost concern about free provision is that some recipients may not use the product, wasting resources (overinclusion). Yet, charging a price to screen out nonusers may screen out poor people who need and would use the product (overexclusion). We report on a randomized controlled trial of a screening mechanism that combines the free provision of chlorine solution for water treatment with a small nonmonetary cost (household vouchers that need to be redeemed monthly in order). Relative to a nonvoucher free distribution program, this mechanism reduces the quantity of chlorine procured by 60 percentage points, but reduces the share of households whose stored water tests positive for chlorine residual by only one percentage point, substantially improving the trade-off between overinclusion and overexclusion.

Willingness to pay for lipid-based nutrient supplements for young children in four urban sites of Ethiopia

Malnutrition in children under 5 years of age is pervasive in Ethiopia across all wealth quintiles. The objective of this study was to determine the willingness to pay (WTP) for a week's supply of Nutributter® (a lipid-based nutrient supplement, or LNS) through typical urban Ethiopian retail channels. In February, 2012, 128 respondents from 108 households with 6-24-month-old children had the opportunity to sample Nutributter® for 2 days in their homes as a complementary food. Respondents were asked directly and indirectly what they were willing to pay for the product, and then participated in market simulation where they could demonstrate their WTP through an exchange of real money for real product. Nearly all (96%) of the respondents had a positive WTP, and 25% were willing to pay the equivalent of at least $1.05, which we calculated as the likely minimum, unsubsidised Ethiopian retail price of Nutributter® for 1 week for one child. Respondents willing to pay at least $1.05 included urban men and women with children 6-24 months old from low-, middle- and high-wealth groups from four study sites across three cities. Additionally, we estimated the initial annual market size for Nutributter® in the cities where the study took place to be around $500 000. The study has important implications for retail distribution of LNS in Ethiopia, showing who the most likely customers could be, and also suggesting why the initial market may be too small to be of interest to food manufacturers seeking profit maximisation.

Learning to Trust Flu Shots: Quasi-Experimental Evidence from the 2009 Swine Flu Pandemic

This paper studies consumer learning in influenza vaccination decisions. We examine consumer learning in influenza vaccine demand within a reduced form instrumental variable framework that exploits differences in risk characteristics of different influenza viruses as a natural experiment to distinguish the effects of learning based on previous influenza vaccination experiences from unobserved heterogeneity. The emergence of a new virus strain (influenza A H1N1/09) during the 2009 'Swine flu' pandemic resulted in two different vaccines being recommended for distinct population subgroups with some people, who were not usually targeted by seasonal vaccination programs, being specifically recommended for the new Swine flu vaccine. We use these differences in vaccination targeting to construct instrumental variables for estimating the effect of past influenza vaccination experiences on the demand for pandemic vaccine. We find large causal effects of previous seasonal vaccination on pandemic vaccination. Causal effects of past influenza vaccination experiences on perceived vaccination safety are likely to be an important pathway linking past vaccination experiences with future vaccine uptake. Our results suggest a significant role of learning in vaccination decisions. Current efforts to expand seasonal vaccination may thus have potentially important long-term effects on future influenza vaccination levels and pandemic preparedness. Copyright © 2016 John Wiley & Sons, Ltd.

Human behaviors: A threat to mosquito control?

In this work, we consider a simple theoretical model that enables us to take into account private human decisions that may interfere with public mosquito control. The model reflects the trade-off between perceived costs and observed efficacy. Our theoretical results emphasize that households may reduce their protective behavior in response to mechanical elimination techniques piloted by a public agent, leading to an increase in the total number of mosquitoes in the surrounding environment and generating a barrier for vector-borne diseases control. Our study is sufficiently generic to be applied to different arboviral diseases. It also shows that vector-control models and strategies have to take into account individual behaviors.

Health and agricultural productivity: Evidence from Zambia

We evaluate the productivity effects of investment in preventive health technology through a randomized controlled trial in rural Zambia. In the experiment, access to subsidized bed nets was randomly assigned at the community level; 516 farmers were followed over a one-year farming period. We find large positive effects of preventative health investment on productivity: among farmers provided with access to free nets, harvest value increased by US$ 76, corresponding to about 14.7% of the average output value. While only limited information was collected on farming inputs, shifts in the extensive and the intensive margins of labor supply appear to be the most likely mechanism underlying the productivity improvements observed.