Evaluating the impact of sugar-sweetened beverages tax on overweight, obesity, and type 2 diabetes in an affluent Asian setting: A willingness-to-pay survey and simulation analysis

BACKGROUND

The potential health effects of taxing sugar-sweetened beverages (SSBs) has been insufficiently examined in Asian contexts. This study aimed to assess the impact of SSB taxation on the prevalence of obesity/overweight and type 2 diabetes mellitus (T2DM) in Hong Kong using a willingness-to-pay (WTP) survey and simulation analysis.

METHODS

A random telephone survey was conducted with 1000 adults from May to June 2020. We used a contingent valuation approach to assess individuals' WTP for SSBs under four tax payment scenarios (5%, 10%, 40%, and 50% of the current market price). Based on the WTP, a simulation analysis was conducted to project changes in SSB purchase and associated reductions in the prevalence of obesity/overweight and T2DM over a 10-year simulation period.

FINDINGS

When 5% and 10% taxation rates were introduced, approximately one-third of the population were unwilling to maintain their SSB purchase. Our simulation demonstrated a gradual decline in the prevalence of obesity/overweight and diabetes with a more pronounced decrease when higher taxation rates were introduced. 10% taxation resulted in a mean reduction of 1532.7 cases of overweight/obesity per 100 thousand population at the sixth year, while T2DM prevalence decreased by 267.1 (0.3%).

CONCLUSIONS

This study underscores the effects of an SSB tax on purchase behaviors and health outcomes in an affluent Asia setting, with a more pronounced influence on adult population. These findings are expected to inform policymakers in making decisions regarding an effective and equitable tax rate on SSBs.

Assessing the perceived effect of non-pharmaceutical interventions on SARS-Cov-2 transmission risk: an experimental study in Europe

We conduct a large (N = 6567) online experiment to measure the features of non-pharmaceutical interventions (NPIs) that citizens of six European countries perceive to lower the risk of transmission of SARS-Cov-2 the most. We collected data in Bulgaria (n = 1069), France (n = 1108), Poland (n = 1104), Italy (n = 1087), Spain (n = 1102) and Sweden (n = 1097). Based on the features of the most widely adopted public health guidelines to reduce SARS-Cov-2 transmission (mask wearing vs not, outdoor vs indoor contact, short vs 90 min meetings, few vs many people present, and physical distancing of 1 or 2 m), we conducted a discrete choice experiment (DCE) to estimate the public's perceived risk of SARS-CoV-2 transmission in scenarios that presented mutually exclusive constellations of these features. Our findings indicate that participants' perception of transmission risk was most influenced by the NPI attributes of mask-wearing and outdoor meetings and the least by NPI attributes that focus on physical distancing, meeting duration, and meeting size. Differentiating by country, gender, age, cognitive style (reflective or intuitive), and perceived freight of COVID-19 moreover allowed us to identify important differences between subgroups. Our findings highlight the importance of improving health policy communication and citizens' health literacy about the design of NPIs and the transmission risk of SARS-Cov-2 and potentially future viruses.

A synthesis of evidence for policy from behavioural science during COVID-19

Scientific evidence regularly guides policy decisions1, with behavioural science increasingly part of this process2. In April 2020, an influential paper3 proposed 19 policy recommendations ('claims') detailing how evidence from behavioural science could contribute to efforts to reduce impacts and end the COVID-19 pandemic. Here we assess 747 pandemic-related research articles that empirically investigated those claims. We report the scale of evidence and whether evidence supports them to indicate applicability for policymaking. Two independent teams, involving 72 reviewers, found evidence for 18 of 19 claims, with both teams finding evidence supporting 16 (89%) of those 18 claims. The strongest evidence supported claims that anticipated culture, polarization and misinformation would be associated with policy effectiveness. Claims suggesting trusted leaders and positive social norms increased adherence to behavioural interventions also had strong empirical support, as did appealing to social consensus or bipartisan agreement. Targeted language in messaging yielded mixed effects and there were no effects for highlighting individual benefits or protecting others. No available evidence existed to assess any distinct differences in effects between using the terms 'physical distancing' and 'social distancing'. Analysis of 463 papers containing data showed generally large samples; 418 involved human participants with a mean of 16,848 (median of 1,699). That statistical power underscored improved suitability of behavioural science research for informing policy decisions. Furthermore, by implementing a standardized approach to evidence selection and synthesis, we amplify broader implications for advancing scientific evidence in policy formulation and prioritization.

Do risk, time and prosocial preferences predict risky sexual behaviour of youths in a low-income, high-risk setting?

Young people in sub-Saharan Africa are particularly at high risk of sexually transmitted infections. Little is known about their preferences and even less about their association with risky sexual behaviour. We conducted incentivized economic experiments to measure risk, time and prosocial preferences in Zimbabwe. Preferences measured at baseline predict biomarker and self-reported measures of risky sexual behaviour gathered 12 months later. We find robust evidence that individuals more altruistic at baseline are more likely to be Herpes Simplex Virus Type-2 (HSV-2) positive 12 months later. Analysis by sex shows this association is driven by our sample of women. Having more sexual partners is associated with greater risk tolerance amongst men and greater impatience amongst women. Results highlight heterogeneity in the association between preferences and risky sexual behaviour.

Penumbral thoughts: Contents of consciousness upon waking

Thoughts shape our experience, choice, and behaviour throughout the day. Yet the content of 'penumbral thoughts'-first thoughts upon waking-has received very little research attention. Across seven independent samples (total N = 829), we used recall and reflection methods, solicited the same day, to understand what individuals think as they regain consciousness. These penumbral thoughts show remarkable thematic consistency: individuals were most likely to reflect on their somatic or psychological state, focus on temporal orientation, and prioritise waking actions. Survey results demonstrate that temporal and spatial orientation are dominated by the current time and the day ahead, rather than the past or other future timescales. Our results provide some insight into the order of priority in consciousness. We conclude that establishing one's temporal position is important to the daily process of 'rebooting' conscious awareness.

Weakened weekdays: lockdown disrupts the weekly cycle of risk tolerance

Risk tolerance decreases from Monday to Thursday and increases on Friday. Antecedents of this weekly risk cycle are difficult to investigate experimentally as manipulating the seven-day cycle is impractical. Here we used temporal disorientation during the UK COVID-19 lockdown to conduct a natural experiment. In two studies, we measured responses to risk in participants with either a strong or weak sense of weekday, after either a short or long period of disruption to their weekly routine by lockdown. In Study 1 (N = 864), the weekly risk cycle was consistent in risk attitude measures specifically to participants who reported a strong sense of weekday. In Study 2 (N = 829), the weekly risk cycle was abolished, even for participants who retained a strong sense of weekday. We propose that two factors sustain the weekly risk cycle. If the sense of weekday is lacking, then weekday will have little effect because the current day is not salient. If weekday associations decay, then weekday will have little effect because the current day is not meaningful. The weekly risk cycle is strong and consistent when (i) sense of weekday is robust and (ii) weekday associations are maintained.

End-of-Life Preferences: A Randomized Trial of Framing Comfort Care as Refusal of Treatment in the Context of COVID-19

BACKGROUND

Rates of advance directive (AD) completion in the United Kingdom are lower than in the United States and other western European countries, which is especially concerning in light of the COVID-19 pandemic. UK residents typically complete an advance decision to refuse care (ADRT), whereas US versions of ADs present a more neutral choice between comfort-oriented or life-prolonging care. The purpose of this study is to test whether this framing affects decision making for end-of-life care and if this is affected by exposure to information about the COVID-19 pandemic.

METHODS

In an online experiment, 801 UK-based respondents were randomly allocated to document their preferences for end-of-life care in a 2 (US AD or UK ADRT) by 2 (presence or absence of COVID-19 prime) between-subjects factorial design.

RESULTS

Most (74.8%) of participants across all conditions chose comfort-oriented care. However, framing comfort care as a refusal of treatment made respondents significantly less likely to choose it (65.4% v. 84.1%, P < 0.001). This effect was exacerbated by priming participants to think about COVID-19: those completing an ADRT were significantly more likely to choose life-prolonging care when exposed to the COVID-19 prime (39.8% v. 29.6%, P = 0.032). Subgroup analyses revealed these effects differed by age, with older participants' choices influenced more by COVID-19 while younger participants were more affected by the AD framing.

CONCLUSIONS

The UK ADRT significantly reduced the proportion of participants choosing comfort-oriented care, an effect that was heightened in the presence of information about COVID-19. This suggests the current way end-of-life care wishes are documented in the United Kingdom could affect people's choices in a way that does not align with their preferences, especially in the context of the COVID-19 pandemic.

HIGHLIGHTS

Participants completing an AD framed as an advance decision to refuse treatment were significantly less likely to choose comfort-oriented care than participants completing an AD with a neutral choice between comfort-oriented and life-prolonging care.Exposure to a COVID-19 prime had an interactive effect on documented preferences in the refusal of treatment condition, with these participants even less likely to choose comfort-oriented care.Policy makers and organizations that design templates for advance care planning, particularly in the time of the COVID-19 pandemic, should be aware how the framing of these forms can influence decisions.

The formation of physician altruism

We study how patient-regarding altruism is formed by medical education. We elicit and structurally estimate altruistic preferences using experimental data from a large sample of medical students (N = 733) in Germany at different progress stages in their studies. The estimates reveal substantial heterogeneity in altruistic preferences of medical students. Patient-regarding altruism is highest for freshmen, significantly declines for students in the course of medical studies, and tends to increase again for last year students, who assist in clinical practice. Also, patient-regarding altruism is higher for females and positively associated to general altruism. Altruistic medical students have gained prior practical experience in healthcare, have lower income expectations, and are more likely to choose surgery and pediatrics as their preferred specialty.

COVID-19 vaccine hesitancy in eight European countries: Prevalence, determinants, and heterogeneity

We examine heterogeneity in COVID-19 vaccine hesitancy across eight European countries. We reveal striking differences across countries, ranging from 6.4% of adults in Spain to 61.8% in Bulgaria reporting being hesitant. We experimentally assess the effectiveness of different messages designed to reduce COVID-19 vaccine hesitancy. Receiving messages emphasizing either the medical benefits or the hedonistic benefits of vaccination significantly increases COVID-19 vaccination willingness in Germany, whereas highlighting privileges contingent on holding a vaccination certificate increases vaccination willingness in both Germany and the United Kingdom. No message has significant positive effects in any other country. Machine learning-based heterogeneity analyses reveal that treatment effects are smaller or even negative in settings marked by high conspiracy beliefs and low health literacy. In contrast, trust in government increases treatment effects in some groups. The heterogeneity in vaccine hesitancy and responses to different messages suggests that health authorities should avoid one-size-fits-all vaccination campaigns.

Bandwagoning, free-riding and heterogeneity in influenza vaccine decisions: An online experiment

'Nudge'-based social norms messages conveying high population influenza vaccination coverage levels can encourage vaccination due to bandwagoning effects but also discourage vaccination due to free-riding effects on low risk of infection, making their impact on vaccination uptake ambiguous. We develop a theoretical framework to capture heterogeneity around vaccination behaviors, and empirically measure the causal effects of different messages about vaccination coverage rates on four self-reported and behavioral vaccination intention measures. In an online experiment, N = 1365 UK adults are randomly assigned to one of seven treatment groups with different messages about their social environment's coverage rate (varied between 10% and 95%), or a control group with no message. We find that treated groups have significantly greater vaccination intention than the control. Treatment effects increase with the coverage rate up to a 75% level, consistent with a bandwagoning effect. For coverage rates above 75%, the treatment effects, albeit still positive, stop increasing and remain flat (or even decline). Our results suggest that, at higher coverage rates, free-riding behavior may partially crowd out bandwagoning effects of coverage rate messages. We also find significant heterogeneity of these effects depending on the individual perceptions of risks of infection and of the coverage rates.

Response to COVID-19: was Italy (un)prepared?

On 31st January 2020, the Italian cabinet declared a 6-month national emergency after the detection of the first two COVID-19 positive cases in Rome, two Chinese tourists travelling from Wuhan. Between then and the total lockdown introduced on 22nd March 2020 Italy was hit by an unprecedented crisis. In addition to being the first European country to be heavily swept by the COVID-19 pandemic, Italy was the first to introduce stringent lockdown measures. The SARS-CoV-2 outbreak and related COVID-19 pandemic have been the worst public health challenge endured in recent history by Italy. Two months since the beginning of the first wave, the estimated excess deaths in Lombardy, the hardest hit region in the country, reached a peak of more than 23,000 deaths. The extraordinary pressures exerted on the Italian Servizio Sanitario Nazionale (SSN) inevitably leads to questions about its preparedness and the appropriateness and effectiveness of responses implemented at both national and regional levels. The aim of the paper is to critically review the Italian response to the COVID-19 crisis spanning from the first early acute phases of the emergency (March-May 2020) to the relative stability of the epidemiological situation just before the second outbreak in October 2020.

When the Future “Spills Under”: General Self-Efficacy Moderates the Influence of Expected Exercise on Present Intellectual Performance

We examined whether an expected future activity (exercise vs. relaxation) impacts a present behavior (performance on an intellectual task) that occurs prior to this activity. Across two experiments ( n = 320 and n = 466), the influence of expected exercise compared to relaxation on present intellectual performance was moderated by general self-efficacy (GSE)—a core personality trait that determines people’s confidence that they can surmount physically or intellectually challenging activities. Participants high in GSE had better intellectual performance when they were expecting to exercise versus relax, whereas the effect reversed under low GSE. Moderated mediation analyses suggested that task-focused attention (i.e., participants’ level of focus while solving the intellectual task) accounted for a significant proportion of variance between the future activity (exercise vs. relaxation) and present intellectual performance across different GSE levels. These findings document a previously unexplored channel through which future expectations shape present outcomes.

Corona-regionalism? Differences in regional responses to COVID-19 in Italy

The paper discusses the responses to the COVID-19 crisis in the acute phase of the first wave of the pandemic (February-May 2020) by different Italian regions in Italy, which has a decentralised healthcare system. We consider five regions (Lombardy, Veneto, Emilia-Romagna, Umbria, Apulia) which are located in the north, centre and south of Italy. These five regions differ both in their healthcare systems and in the extent to which they were hit by the first wave of COVID-19 pandemic. We investigate their different responses to COVID-19 reflecting on seven management factors: (1) monitoring, (2) learning, (3) decision-making, (4) coordinating, (5) communicating, (6) leading, and (7) recovering capacity. In light of these factors, we discuss the analogies and differences among the regions and their different institutional choices.

Heterogeneity in Risk-Taking During the COVID-19 Pandemic: Evidence From the UK Lockdown

In two pre-registered online studies during the COVID-19 pandemic and the early 2020 lockdown (one of which with a UK representative sample) we elicit risk-tolerance for 1,254 UK residents using four of the most widely applied risk-taking tasks in behavioral economics and psychology. Specifically, participants completed the incentive-compatible Balloon Analog Risk Task (BART) and the Binswanger-Eckel-Grossman (BEG) multiple lotteries task, as well as the Domain-Specific Risk-Taking Task (DOSPERT) and the self-reported questions for risk-taking used in the German Socio-economic Panel (SOEP) study. In addition, participants in the UK representative sample answered a range of questions about COVID-19-related risky behaviors selected from the UCL COVID-19 Social Survey and the ICL-YouGov survey on COVID-19 behaviors. Consistently with pre-COVID-19 times, we find that risk tolerance during the UK lockdown (i) was higher in men than in women and (ii) decreased with age. Undocumented in pre-COVID-19 times, we find some evidence for healthier participants displaying significantly higher risk-tolerance for self-reported risk measures. We find no systematic nor robust patterns of association between the COVID-19 risky behaviors and the four risk-taking tasks in our study. Moreover, we find no evidence in support of the so-called "risk compensation" hypothesis. If anything, it appears that participants who took greater risk in real-life COVID-19-relevant risky behaviors (e.g., isolating or taking precautions) also exhibited higher risk-tolerance in our experimental and self-reported risk-taking measures.

Improving risk perception and uptake of voluntary medical male circumcision with peer-education sessions and incentives, in Manicaland, East Zimbabwe: study protocol for a pilot randomised trial

BACKGROUND

Voluntary medical male circumcision (VMMC) is a key component of combination HIV-prevention programmes. Several high-HIV-prevalence countries in sub-Saharan Africa, including Zimbabwe, are looking to scale up VMMC activities. There is limited evidence on how a combination of social learning from peer education by a role model with different behavioural incentives influences demand for VMMC in such settings.

METHODS/DESIGN

This matched-cluster randomised controlled trial with 1740 participants will compare two behavioural incentives against a control with no intervention. In the intervention clusters, participants will participate in an education session delivered by a circumcised young male ("role model") on the risks of HIV infection and the benefits from medical male circumcision. All participants will receive contributions towards transport costs to access medical male circumcision at participating clinics. Via blocked randomisation, in the intervention clusters participants will be randomly assigned to receive one of two types of incentives - fixed cash payment or lottery payment - both conditional on undergoing surgical VMMC. In two sites, a community-led intervention will also be implemented to address social obstacles and to increase support from peers, families and social structures. Baseline measures of endpoints will be gathered in surveys. Follow-up assessment at 6 months will include self-reported uptake of VMMC triangulated with clinic data.

DISCUSSION

This is the first trial to pilot-test social learning to improve risk perception and self-efficacy and to address the fear of pain associated with VMMC and possible present-biased preferences with front-loaded compensations as well as fixed or lottery-based cash payments. This study will generate important knowledge to inform HIV-prevention policies about the effectiveness of behavioural interventions and incentives, which could be easily scaled-up.

TRIAL REGISTRATION

This trial has been registered on ClinicalTrials.gov (identifier: NCT03565588). Registered on 21 June 2018.

Improving risk perception and uptake of pre-exposure prophylaxis (PrEP) through interactive feedback-based counselling with and without community engagement in young women in Manicaland, East Zimbabwe: study protocol for a pilot randomized trial

BACKGROUND

HIV incidence in adolescent girls and young women remains high in sub-Saharan Africa. Progress towards uptake of HIV prevention methods remains low. Studies of oral pre-exposure prophylaxis (PrEP) have shown that uptake and adherence may be low due to low-risk perception and ambivalence around using antiretrovirals for prevention. No evidence exists on whether an interactive intervention aimed at adjusting risk perception and addressing the uncertainty around PrEP will improve uptake. This pilot research trial aims to provide an initial evaluation of the impact of an interactive digital tablet-based counselling session, correcting risk perception, and addressing ambiguity around availability, usability, and effectiveness of PrEP.

METHODS/DESIGN

This is a matched-cluster randomized controlled trial which will compare an interactive tablet-based education intervention against a control with no intervention. The study will be implemented in eight sites. In each site, two matched clusters of villages will be created. One cluster will be randomly allocated to intervention. In two sites, a community engagement intervention will also be implemented to address social obstacles and to increase support from peers, families, and social structures. A total of 1200 HIV-negative young women aged 18-24 years, not on PrEP at baseline, will be eligible. Baseline measures of endpoints will be gathered in surveys. Follow-up assessment at six months will include biomarkers of PrEP uptake and surveys.

DISCUSSION

This will be the first randomized controlled trial to determine whether interactive feedback counselling leads to uptake of HIV prevention methods such as PrEP and reduces risky sexual behavior. If successful, policymakers could consider such an intervention in school-based education campaigns or as post-HIV-testing counselling for young people.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03565575. Registered on 21 June 2018.

Looking at Spillovers in the Mirror: Making a Case for "Behavioral Spillunders"

Behavioral spillovers refer to the influence that a given intervention targeting behavior 1 exerts on a subsequent, non-targeted, behavior 2, which may or may not be in the same domain (health, finance, etc.) as one another. So, a nudge to exercise more, for example, could lead people to eat more or less, or possibly even to give more or less to charity depending on the nature of the spillover. But what if spillovers also operate backward; that is, if the expectation of behavior 1 influences behavior 0 that precedes it? For example, a person may form an intention to exercise prompted by a policy intervention but overeat at present as a result. We define such a possibility as a "spillunder." In the proposed article, we critically review the few papers that we have identified through a narrative literature review which have demonstrated spillunder effects to date, and we propose a conceptual framework. Based on evidence about the human mind and behavior from psychology and economics, we argue that spillunder effects may be more common than the limited empirical findings suggest. We propose six representative mechanisms through which the prospect of behavior 1 may impact behavior 0: executive functions, moral licensing and moral cleansing, emotion regulation, energization, construal level, and savoring and dread. We further discuss the policy and practical implications of spillunder effects and examine methodological issues that need to be considered when empirically testing these effects. As with our earlier paper on spillovers, we aim to motivate other behavioral scientists to research behavioral spillunders more systematically and extensively, and to prompt decision makers to consider these effects when designing behavioral interventions.

Physician altruism and moral hazard: (no) Evidence from Finnish national prescriptions data

We test the physicians' altruism and moral hazard hypotheses using a national panel register containing all 2003-2010 statins prescriptions in Finland. We estimate the likelihood that physicians prescribe generic versus branded versions of statins as a function of the shares of the difference between what patients have to pay out of their pocket and what is covered by the insurance, controlling for patient, physician, and drug characteristics. We find that the estimated coefficients and the average marginal effects associated with moral hazard and altruism are nearly zero, and are orders of magnitude smaller than the ones associated with other explanatory factors such as the prescriptions' year and the physician specialization. When the analysis distinctly accounts for both the patient and the insurer shares of expenditure, the estimated coefficients directly reject the altruism and moral hazard hypotheses. Instead, we find strong and robust evidence of habits persistence in prescribing branded drugs.

How to Measure Behavioral Spillovers: A Methodological Review and Checklist

A growing stream of literature at the interface between economics and psychology is currently investigating 'behavioral spillovers' in (and across) different domains, including health, environmental, and pro-social behaviors. A variety of empirical methods have been used to measure behavioral spillovers to date, from qualitative self-reports to statistical/econometric analyses, from online and lab experiments to field experiments. The aim of this paper is to critically review the main experimental and non-experimental methods to measure behavioral spillovers to date, and to discuss their methodological strengths and weaknesses. A consensus mixed-method approach is then discussed which uses between-subjects randomization and behavioral observations together with qualitative self-reports in a longitudinal design in order to follow up subjects over time. In particular, participants to an experiment are randomly assigned to a treatment group where a behavioral intervention takes place to target behavior 1, or to a control group where behavior 1 takes place absent any behavioral intervention. A behavioral spillover is empirically identified as the effect of the behavioral intervention in the treatment group on a subsequent, not targeted, behavior 2, compared to the corresponding change in behavior 2 in the control group. Unexpected spillovers and additional insights (e.g., drivers, barriers, mechanisms) are elicited through analysis of qualitative data. In the spirit of the pre-analysis plan, a systematic checklist is finally proposed to guide researchers and policy-makers through the main stages and features of the study design in order to rigorously test and identify behavioral spillovers, and to favor transparency, replicability, and meta-analysis of studies.

Doctor-patient differences in risk and time preferences: A field experiment

We conduct a framed field experiment among patients and doctors to test whether the two groups have similar risk and time preferences. We elicit risk and time preferences using multiple price list tests and their adaptations to the healthcare context. Risk and time preferences are compared in terms of switching points in the tests and the structurally estimated behavioural parameters. We find that doctors and patients significantly differ in their time preferences: doctors discount future outcomes less heavily than patients. We find no evidence that doctors and patients systematically differ in their risk preferences in the healthcare domain.

In Sickness but Not in Wealth

We present results from a hypothetical framed field experiment assessing whether risk preferences significantly differ across the health and financial domains when they are elicited through the same multiple price list paired-lottery method. We consider a sample of 300 patients attending outpatient clinics in a university hospital in Athens during the Greek financial crisis. Risk preferences in finance were elicited using paired-lottery questions with hypothetical payments. The questions were adapted to the health domain by framing the lotteries as risky treatments in hypothetical health care scenarios. Using maximum likelihood methods, we estimated the degree of risk aversion, allowing for the estimates to be dependent on domain and individual characteristics. The subjects in our sample, who were exposed to both health and financial distress, tended to be less risk averse in the financial domain than in the health domain.

Paying people to eat or not to eat? Carryover effects of monetary incentives on eating behaviour

There is no evidence comparing head-to-head the effects of monetary incentives to act and to abstain from acting on behaviour. We present an experiment, conducted between June and September 2012, that directly compares the effects of those two different monetary incentive schemes on eating behaviour: we evaluate incentives to eat against incentives not to eat. A large number of participants (n = 353) had bowls of sweets next to them while they watched different videos over two experimental sessions that were two days apart. Sweets eating was monitored and monetary incentives to eat or not to eat were introduced during one of the videos for participants randomly allocated to these conditions. Our results show that, while both types of incentives were effective in changing sweets-eating behaviour when they were in place, only incentives not to eat had significant carryover effects after they were removed. Those effects were still significant two days after the monetary incentives had been eliminated. We also present some additional results on personality and health-related variables that shed further light on these effects. Overall, our study shows that incentives not to eat can be more effective in producing carryover effects on behaviour in domains like the one explored here.

•

We experimentally compare the effects of different incentives on eating behaviour.

•

Subjects had bowls of sweets next to them while they watched videos in lab sessions.

•

Incentives to eat or not to eat were randomly allocated during one of the videos.

•

Both incentives were effective in changing eating behaviour when they were in place.

•

Only incentives not to eat had significant carryover effects after being removed.

Digit ratio (2D:4D) and altruism: evidence from a large, multi-ethnic sample

We look at the links between the Digit Ratio—the ratio of the length of the index finger to the length of the ring finger—for both right and left hands, and giving in a Dictator Game. Unlike previous studies with exclusively Caucasian subjects, we consider a large, ethnically diverse sample. Our main results are as follows. First, for Caucasian subjects we estimate a significant positive regression coefficient for the right hand digit ratio and a significant negative coefficient for its squared measure. These results replicate the findings of Brañas-Garza et al. (2013), who also observe an inverted U-shaped relationship for Caucasian subjects. Second, we are not able to find any significant association of the right hand digit ratio with giving in the Dictator Game for the other main ethnic groups in our sample, nor in the pooled sample. Third, we find no significant association between giving in the Dictator Game and the left hand digit ratio.

Should I pay for your risky behaviours? Evidence from London

We investigate the extent to which respondents from a general population sample in London (July-August 2011) agree or disagree with the NHS covering the healthcare costs related to five risky health behaviours: overeating, unhealthy diet, sedentary life, excess of alcohol, and smoking. For each behaviour, we also directly explore the main factors associated with the likelihood to agree or disagree. Half of the respondents (N=146) manifest agreement with the idea. Wider agreement exists for covering the costs associated smoking, heavy drinking, and sedentary lives than with overeating, or poor diets. With the exception of alcohol drinking and sedentary life, there is an almost one-to-one relationship between the agreement that the NHS should pay the healthcare costs associated with a specific behaviour, and the respondents' actual engagement in that behaviour. Those at higher risk of depending on publicly funded healthcare, are more likely to agree.

Label, nudge or tax? A review of health policies for risky behaviours

This work proposes a critical, non systematic, review of the three main lines of health policy interventions to deal with risky behaviours, such as over-eating, smoking, sedentary lives, and excess alcohol drinking, namely: i) the release of information on health risks and consequences; ii) the use of incentives; and iii) direct policy intervention in markets, through regulation and taxation. First, the health and economic impact of the risky behaviours epidemics are briefly described. Then a critical review follows on the evidence existing on the effectiveness of each type of intervention. The review will also highlight the public health approach staying beyond each type of policy on risky behaviours and critically consider them within the context of more general health and social policy interventions.

The effects of hospitals' governance on optimal contracts: bargaining vs. contracting

We propose a two-stage model to study the impact of different hospitals' governance frameworks on the optimal contracts designed by third-party payers when patients' disease severity is the private information of the hospital. In the second stage, doctors and managers interact within either a bargaining or a contracting scenario. In the contracting scenario, managers offer a contract that determines the payment to doctors, and doctors decide how many patients to treat. In the bargaining scenario, doctors and managers strategically negotiate on both the payment to doctors and the number of patients to treat. We derive the equilibrium doctors' payments and number of treated patients under both scenarios. We then derive the optimal contract offered by the government to the hospital in the first stage. Results show that when the cost of capital is sufficiently low, the informational rent is lower, and the social welfare is higher, in the contracting scenario.