A comparison of costs and data quality of three health survey methods: mail, telephone and personal home interview

Health response by questionnaire in arsenic-exposed populations

The health status of populations exposed to arsenic through drinking water was determined by a mailed questionnaire. Participants were selected from three communities located in Nevada with 1977 tap water arsenic levels of approximately 0.1 mg/l and one California community with 1977 levels around 0.39 mg/l. The questionnaire responses were obtained in 1979 from the four exposed communities and compared to those of a Wyoming community whose tap water levels of arsenic were less than 0.001 mg/l in 1979. No difference in health status for gastrointestinal, neurological, musculoskeletal, circulatory and skin disorders was found. The average number of years of consumption given by length of residence was 6-16 years. We conclude that the health status of these arsenic-exposed populations has not been adversely affected.

Prevalence and correlates of hospital-based autologous blood programs: a statewide survey

To identify potential barriers to use of autologous blood procurement to minimize homologous blood transfusion needs during elective surgery, the authors conducted a telephone survey of 120 blood bank directors, representing 138 Ohio hospitals. The prevalence of autologous blood procurement facilities, estimated volume of autologous blood, and attitudes and perceptions of the directors toward autologous blood predeposit programs were assessed. Analysis of the data indicated that 30% of Ohio hospitals have autologous blood procurement facilities; larger hospitals were more likely to have this facility. Overall, 5.5% of transfusions involve predeposited autologous blood. No significant differences were found according to hospital bed size or whether the hospital had a procurement facility. Blood bank directors perceived surgeons to be knowledgeable about autologous predeposit; patient demand and surgical practice were felt to be more effective in promoting the use of autologous blood at the hospital than were blood bank efforts. Directors who had autologous predeposit procurement facilities perceived that the facility provided a marketing advantage. Respondents from larger hospitals were more likely to perceive that these programs could be financially self-sufficient. The authors conclude that an economic cost-benefit analysis of hospital-based autologous blood procurement programs is important. Positive findings may influence transfusion services to adopt autologous blood procurement programs, whereas negative findings may convince hospitals that community blood donor facilities can provide better autologous blood procurement.

Investigating the proxy effect and the saliency principle in household based postal questionnaires

STUDY OBJECTIVE

The aim was to investigate two possible sources of bias inherent in using a household based postal questionnaire, the "proxy effect", inaccurate reporting about characteristics of others, and the "saliency principle", reporting of only the most salient features. This is of importance in surveys concerned with screening the population to identify individuals with certain characteristics, and so possibly relying on one member of the household to reply on behalf of all others.

DESIGN AND SETTING

A two stage survey of disablement in the population was undertaken. A first phase postal questionnaire was sent to 25,168 households in Calderdale, West Yorkshire, England, to ascertain the prevalence of physical disability and of troubles with the joints. The second phase comprised in depth interviews with a sample of individuals identified in the first phase as being disabled.

RESPONDENTS

A total of 21,889 postal questionnaires were returned (87%) representing households containing 42,826 people aged 16 years and over. A disproportionately stratified random sample of 950 respondents reporting disability was taken in the second phase. Of these 891 were still available, and 838 (94%) were interviewed.

MEASUREMENTS AND MAIN RESULTS

The postal questionnaire found that almost 29% of those who lived "alone" (without another adult) reported some level of disability, compared to only 10% of those who lived with others. The difference remained significant after standardisation. This apparent underreporting or "proxy effect" was present for reporting about disability overall, but not for severe disability (dependence on help of others), which suggests the operation of the "saliency principle". Reporting on joint troubles appeared to be affected by the proxy effect both for any joint problems, and when more than five joints were affected. Analysis of a small set of postal questionnaires from respondents who reported joint problems only at interview and where we could identify who had completed the postal questionnaire supports the hypothesis of a proxy effect; two thirds of the original postal questionnaires had been completed by a proxy. The results were further complicated by an interaction between reporting of disability and joint troubles: the greater the level of disability, the less likely the reporting of joint troubles.

CONCLUSIONS

The findings have general implications for studies involving postal household screening questionnaires, and raises additional concerns about those that are multitopic in content. In surveys of symptoms and minor disability, a proxy effect is likely to be operative. This effect is not apparent for obvious and long standing problems such as dependence on others for help. However the interaction between the reporting of disability and joint symptoms carries important implications for the development of multitopic postal screening questionnaires.

Cohort reconstruction: which infants can be restudied at school age?

Longer-term follow-up of infants with specific health concerns, such as low birthweight, is critical to assessing the effect of medical interventions. This report examines the approach of reconstructing previously studied cohorts in terms of the factors discriminating between respondents and non-respondents. Follow-up was attempted during 1987-1988 for 1875 children born during a 6-month period in 1978 in three geographically defined regions in the United States, for whom 1-year assessments of health and developmental status were obtained at 1 year of age as part of a previous study. For a 25% sample, participation involved a clinic visit for developmental assessments; for the remainder an interview by telephone or home visit. Follow-up was obtained for 72.5% of the cohort. Refusal rates were low (7%); most non-response was due to an inability to locate the families. Predictors of non-response reflected primarily low socio-economic status; completion rates were not influenced by mode of assessment. The role of a tracing agency is discussed. We conclude that cohort reconstruction is feasible with response rates comparable to some prospective studies with ongoing cohort maintenance.

Women's perceptions of screening mammography

A random sample of women in Sydney were interviewed by telephone to determine their knowledge about and attitudes to mammography. A response rate of 56 per cent (628 women) was obtained. While the majority of women had had some experience with breast cancer, knowledge about which age groups were most at risk and treatment alternatives was limited. Only about half of the sample had heard about screening mammography before the survey. However, when a simple explanation was given, 79 per cent expressed a favourable attitude toward it. Only 22 per cent of women thought of themselves as being personally susceptible to breast cancer; the proportion was lower in women over 60 than in those in their 40s. Morbid concern about breast cancer was rare. About a quarter of the sample expressed concern about mammographically induced exposure to radiation. Attitudes and perceptions of personal susceptibility were not associated with knowledge about risks of breast cancer. However, having a favourable attitude and a lack of concern about radiation were associated with previously having heard about screening mammography. Women speaking a language other than English at home and from households where the main income earner was in an unskilled occupation were least likely to have heard of screening mammography. Suggestions for data-based recruitment strategies are discussed.

Conservative management of temporomandibular disorders: a posttreatment comparison between patients from a university clinic and from private practice

Long-term (1 to 7.5 years) follow-up evaluations of 110 adult patients who were seen for diagnosis and treatment of symptoms related to myofascial problems (MP), internal derangement (ID), or both were conducted by means of telephone interview. One half of the patients were seen at the Northwestern University Dental School TMJ Clinic, while the other half were seen in the private office of one author (H. T. P.). The purpose of this study was to evaluate patient response to conservative therapy combined with advice about self-management, as compared with the response to advice only. Further, we desired to compare treatment outcomes among (1) diagnostic categories ID, MP, and ID plus MP, (2) clinic patients and private patients, and (3) patients with acute disease and those with chronic disease. Chronic disease was identified as that in which pretreatment symptoms had persisted for more than 4 months. The ridit analysis was used to assess differences in outcomes for patients in the three diagnostic categories and for clinic patients compared with private patients. The results revealed no significant differences. There was a trend for patients with acute conditions to improve more than those with chronic problems; however, further research is needed to determine whether a correlation exists between symptom duration and treatment outcome. At the time of the follow-up evaluation, 88% of all patients reported substantial or total improvement in their symptoms of pain and dysfunction. Therefore, conservative therapy, including advice about self-management, was found to be both adequate and appropriate for most of these patients.

Prevalence of temporomandibular symptoms in a large United States metropolitan area

The prevalence of five symptoms of temporomandibular disorder and associated symptoms of pain, headache, and stress was estimated in a random telephone survey of a large United States metropolitan area. The prevalences for nocturnal bruxing, joint noise with use, soreness on waking, soreness with use, and diurnal clenching were roughly equivalent (ranging from 8% to 12%) and were within the range of prevalences reported in previous studies. Overall, 149 of the 500 respondents reported one or more of the five symptoms. Symptoms were not more prevalent among women than men, but were more prevalent among younger respondents. Soreness on waking and daytime clenching were the only symptoms significantly associated with report of pain. Pain was more commonly reported by respondents with multiple (four or five) symptoms. The results are compared with those of previous random surveys, and limitations to generalization of the present findings are discussed.

Fate of incorrectly addressed mailed questionnaires

Mail surveys are a widely used and often inexpensive method for conducting epidemiologic studies, but may suffer from poor response rates. Some of this nonresponse may be due to letters that never reach study subjects rather than nonparticipation. We mailed letters to invalid addresses and to fictitious occupants at valid addresses in order to determine the proportion of letters that were not returned to us by the postal service as undeliverable. All letters mailed to invalid addresses were returned, whereas 13.3% (95% Cl 2.0-24.7%) of letters sent to fictitious occupants were not. Because some undeliverable mail is not returned, investigators may erroneously assume nonresponse for some subjects who never have the opportunity to participate.

Patient literacy and the readability of smoking education literature

This study was designed to determine if primary care clinic patients read at a level congruent to the reading grade level of available smoking literature. Reading estimates of smoking education literature (N = 49) ranged from grade 3 to college level (median = 9.5). Reading skills of 258 smoking patients were estimated by reported years of schooling (median = 10), and by scores on the Wide-Range Achievement Test (median = 6). A serious disparity existed between the reading estimates of smoking education literature and the literacy skills of patients in our sample.

Validity of telephone surveys in assessing cigarette smoking in young adults

Self-reports of cigarette smoking in a sample of young adults, aged 17 to 21 (n = 359) obtained by telephone were validated by home interview and saliva cotinine measurement. While most subjects were in agreement for their reported behaviors, the telephone methodology underestimated cigarette smoking rates by 3 to 4 per cent. Reported quitting by telephone was an unstable category with 35 per cent of quitters reporting smoking on home interview. Reliance on telephone methods alone may underestimate smoking behavior. Validation of surveys, preferably by biochemical methods, is recommended.

An 11-year follow-up study of 110 depressed patients

In 1972 the World Health Organization organized a cross-cultural five-centre study of depressive disorders. This report is concerned with data collected, after an 11-year follow-up period, in the sample of 110 depressed patients in Montreal, Canada. Eighty-five percent were traced and 59% were interviewed. Of 93 patients, 20 were dead at the follow-up date, 11 by suicide. Fifty-two percent of patients were receiving psychiatric treatment at follow-up, but there was no relation between psychiatric morbidity and treatment-seeking. Moderate or severe impairment of social functioning was present in 32%; in women, a trend linking the presence of social impairment and the time spent in episodes was observed. Of the episodes of psychiatric illness recorded after the index episode, 86% were diagnosed as depressive, 14% as unspecified affective disorder. The mean durations of the index and four subsequent episodes were 10, 11, 7, 11, and 2 months respectively. At least one recurrence after the index episode was reported by 78%, at least four recurrences by 19%. Episodes lasted at least one year in 5%, 4%, 6%, and 6% in the first, second, third and fourth episodes respectively. Sixteen percent were depressed for at least one year and 31% for at least 2 years. There was a marked trend from inpatient to outpatient treatment and from ECT to drug therapy over time. Twenty-two percent reported either moderate or severe problems with alcohol or substance abuse. There was a statistically significant association between the amount of time patients spent in depressive episodes and the number of life events they reported.(ABSTRACT TRUNCATED AT 250 WORDS)