Study of return rate and return time of undeliverable postal letters

Postal questionnaires are widely used to collect data in health research and epidemiologic studies. One problem related to mail surveys is the availability of an up-to-date and accurate list of people in the population from which to draw the sample for the survey. For the identification of incorrect postal addresses it is important that all incorrectly addressed mails are returned as undeliverable. This study examines the proportion of unreturned postal letters that were sent to incorrect addresses. We sent 339 letters to existing addresses throughout Germany, but used fictional names name of persons. Three hundred and three letters (98.2%) were returned as undeliverable. The return rates only slightly differed by layout of the envelopes, region and deliverer.     

Assessing the burden of undeliverable immunization reminder and recall notifications

Purpose

To assess the completeness and accuracy of parent contact information for the delivery of mailed reminder/recall notices using a statewide immunization information system (IIS).

Methods

The Michigan Care Improvement Registry (MCIR) was used to generate reminder and recall notifications for children ages 6 months–19 years in Michigan (2008–2009). Mailed notifications were classified as being undeliverable if they were returned to the local health department (LHD) by the US Postal Service.

Results

20,377 notifications were mailed and 5182 (26%) were undeliverable. Undeliverable notification increased with age (reference, 6–18 months): 19–35 months (OR = 1.27), 36–71 months (OR = 3.03) and adolescents 11–19 years (OR = 4.94). Children enrolled in Medicaid (OR = 0.76) were less likely to have an undeliverable notification compared to their non-enrolled counterparts, but children who had previously received some (OR = 1.07) or all vaccinations (OR = 2.43) at an LHD were more likely to have an undeliverable notification.

Conclusion

Undeliverable reminder/recall notifications are most likely among adolescents. Efforts to identify alternate sources of parent contact information may be an important strategy to improve the successful delivery of reminder/recall notifications, especially for adolescents.     

Using commercial telephone directories to obtain a population-based sample for mail survey of women of reproductive age

In the United States, sampling women of reproductive age from the general population for research purposes is a challenge. Even more difficult is conducting a population-based study of couples attempting pregnancy to assess fecundity and fertility or related impairments. To address the problem of obtaining representative samples from the population in order to study such health-related issues, a commercially and readily available CD-ROM telephone directory was used and tested as a sampling framework for studies aimed at enrolling gravid women aged 18-44 years. A self-administered questionnaire (SAQ) was mailed to a stratified random sample of 10 005 (3%) households in Erie County, NY, USA. Overall, 17% of the questionnaires were undeliverable despite updating all addresses with residential software before mailing. Thirteen per cent (n = 1089) of the households returned completed questionnaires, of which 35% (n = 377) were completed by women aged 18-44 years. Using 1990 census information for zip code, respondents were more likely to be white and to have higher median household incomes than non-respondents. Of the 377 women who completed the questionnaire, 79% had been pregnant at least once, 5% reported being unable to become pregnant, and 16% reporting never trying to become pregnant. Despite the overall low response to the SAQ, the sampling framework captured a diverse group of women of reproductive age who reported various fecundity and fertility outcomes. The use of low-cost commercially available software linked to census data for selecting samples of women or couples for reproductive and perinatal research may be possible; however, oversampling of households, use of incentives and follow-up of non-respondents is needed to ensure adequate sample sizes.     

Occupational therapy practitioners' comfort level and preparedness in working with individuals who are gay, lesbian, or bisexual

Occupational therapists and other allied health professionals face diversity with their clients, including sexual orientation. The purpose of this study was to determine the preparedness and comfort level of occupational therapy practitioners in working with gay, lesbian, and bisexual clients. A 23-item survey was mailed to 1,051 practitioners in a midwestern state. Eighty-eight were undeliverable and 373 usable surveys were returned, yielding a 39% response rate. Most respondents felt prepared and comfortable to work with clients who are gay, lesbian, or bisexual, and 48% agreed that sexuality influences occupational choices. Twenty-nine percent agreed that sexual orientation influences occupational therapy treatment. Less than 20% of the respondents, however, received education and used inclusive language in their documentation, and only 14% reported having resources and support services for clients who are gay, lesbian, or bisexual. Effective education and policy-making strategies are necessary to ensure an accepting therapeutic environment and respect for the role of sexual orientation in the intervention process.     

Adapting the Pregnancy Risk Assessment Monitoring Survey to Enhance Locally Available Data: Methods

Despite the increasing emphasis on pre- and interconception planning, perinatal data available to local municipalities and organizations is often limited to that on the birth certificate. A partnership between a local health department and an academic medical center sought to overcome this gap. Using the core questions from the Pregnancy Risk Assessment Monitoring System (PRAMS) and a stratified random sample methodology (by income) in a county with ~8,000 annual births we mailed 2,462 surveys to mothers who gave birth between May 2009 and April 2010. Mailings occurred at 4–5 months postpartum. Low income mothers (those with a Medicaid-funded delivery and/or prenatal WIC enrollment) were oversampled based on a projected response rate of 35 % (rate for non-low income was 55 %). Over 1,000 usable surveys were returned and linked with birth certificate data. Target response rates were achieved. 9.4 % of addresses for low income mothers were undeliverable (vs. 4.2 % of non-low income). Both low and non-low income respondents were more likely to be over age 18 and White. After statistical adjustments the survey dataset was demographically similar to the original birth data. Personnel and non-personnel costs per usable survey exceeded $20. Collecting local data using a modified PRAMS methodology is feasible but requires expertise in survey, data management and birth certificate data and local knowledge about survey response patterns. These types of data can serve to inform policy and program planning and provide data to support relevant funding requests.     

Impact of reminders and method of questionnaire distribution on patient response to mail-back satisfaction survey.

Nonresponse and methods of data collection could affect satisfaction measurement. The goal of this study was to estimate the impact of (1) nonresponse and (2) distribution method on evaluation of patient satisfaction in a mail-back study measuring patient opinion of medical and nursing care. The study was conducted in an adult hospital. Patients were pseudo-randomized according to the initial mode of questionnaire distribution (given at hospital or sent by mail). Three reminders were made at 1-week intervals to nonrespondents, regardless of the method of initial questionnaire distribution. Groups were distinguished according to the delay of response: initial (before any reminder), middle (after one or two mailed reminders), and late respondents (after mailed reminders plus telephone contact). The study included consecutively discharged patients to obtain 300 patients per arm. 482 patients returned the questionnaire (248 in the group receiving the questionnaire at the hospital and 234 in the other group). Groups were compared for satisfaction scores and delay of response. Early respondents were compared with middle and late respondents for patient characteristics, modality of hospital care, and satisfaction scores. Multivariate analyses were performed. Participation rate before any reminder was higher when the questionnaire was mailed than when it was given at the hospital (45% versus 39.7%, p = 0.03). The initial method of distribution did not influence patient satisfaction level. Satisfaction did not differ between respondents with or without reminders. Distributing questionnaires by mail may be preferred to distribution at discharge to optimize response rate. Reminders do not seem necessary to estimate satisfaction of overall potential respondents.     

Prenotification but not envelope teaser increased response rates in a bulimia nervosa mental health literacy survey: A randomized controlled trial

ObjectivesUnderstanding attitudes to mental health issues can inform public health interventions. However, low response rates may contribute to nonresponse bias. In a randomized controlled trial we examined the effect of sending a prenotification postcard before the questionnaire and the placement of a short message on the survey envelope (teaser) on response rates to a mailed questionnaire about bulimia nervosa “mental health literacy”.Study Design and SettingQuestionnaires were mailed to 3,010 adults (50.6% female and 49.4% male) aged 18–65 years. In a 2 (pre-notification–present; absent) by 2 (teaser–present; absent) design, questionnaire recipients were randomly allocated to the experimental strategies. Outcomes considered were response rate, response time, and cost.ResultsThe overall response rate was 22.0%. Significant main effects showed higher response rates for the use of prenotification (present = 23.6%; absent = 20.3%), among female participants, and older participants. A significant interaction of teaser by gender indicated lower response rates for men who received the teaser but not for women. Older participants returned the questionnaire more promptly than younger participants. Females—but not males—who received the teaser were slower to return the questionnaire. Higher response rates for participants receiving the postcard compensated for increased costs, particularly for males and older participants.ConclusionResponse rates to a mental health postal survey can be increased through the use of prenotification.     

The impact of survey nonresponse bias on conclusions drawn from a mammography intervention trial

BACKGROUND AND OBJECTIVE: This study demonstrates the impact of survey nonresponse bias on conclusions from a mammography trial targeting a disadvantaged population. METHODS:The trial randomized 1558 women to three interventions designed to promote repeat mammography: mailed reminder (minimum group); mailed thank-you card, patient newsletters, and reminder (maximum group); and no mailings (control group). The primary outcome, repeat mammogram within 15 months, was assessed from administrative and phone survey data. RESULTS: Administrative estimates revealed a statistically significant difference of 7% between the maximum and control groups on the primary outcome. Survey estimates (response rate 80%) revealed no significant differences. The differences by data source were traced to a survey nonresponse bias. There was a statistically significant difference of 16% between the maximum and control groups among survey nonrespondents for the primary outcome, but there were no differences among survey respondents. CONCLUSION: The findings reiterate that even a low survey nonresponse rate can bias study conclusions and suggest studies targeting disadvantaged populations should avoid relying solely on survey data for outcome analyses.     

Telephone reminder calls increased response rates to mailed study consent forms

BACKGROUND: This study assessed the impact of follow-up reminder phone calls on response rates to a mailed consent form packet. METHODS: Patients with rheumatoid arthritis were invited to enroll in a study by signing and returning consent forms by mail. Patients not returning completed study consent forms were called and reminded to return the signed consent forms. RESULTS: Among 724 mailed consent form packets, 376 (52%) were returned without further follow-up. Follow-up reminder calls were made to 220 of the 348 patients who did not return signed consent forms. Among subjects contacted by phone, 67 (31% of those called) returned signed consent forms. CONCLUSION: Follow-up reminder phone calls raised the overall consent rate of 52 to 61%, suggesting that they can be an effective technique in increasing response rates.     

A comparison of response rate and time according to the survey methods used: A randomized controlled trial

The purpose of this study was to evaluate the effects of recorded and standard deliveries, and stamped and franked return envelopes in a postal survey of Korean–Vietnam veterans. Nine hundred veterans were randomly divided into four subgroups. A randomized controlled trial was conducted for two mailing strategies. The 52 study subjects to whom mail was undeliverable and 36 additional study subjects found not to be residing at the listed addresses were excluded from the study. The 699 (86%) surveys were returned within 39 business days after the first mailing. The response rate for the recorded delivery (88%) was significantly higher than that of the standard delivery (82%)(p = 0.03), and the response rate of the stamped return envelops (88%) was higher than that of the franked return envelops (85%)(p = 0.27). The replies for the recorded and standard deliveries arrived an average of 10.2 and 9.9 business days, respectively, after the first mailing (p = 0.60). The average times of the responses for the stamped and franked return envelopes were 9.8 and 10.4 business days, respectively (p = 0.25). Recorded deliveries significantly increased the response rate compared to standard deliveries, and stamped return envelops slightly increased the response rate a little compared to franked return envelops. The timing of response of recorded deliveries was similar to that of standard deliveries but the volume of response of recorded deliveries was higher than that of standard deliveries.This revised was published online in April 2005. In the previous version the article category was missing.     

Postal survey on airborne occupational exposure and respiratory disorders in Norway: causes and consequences of non-response.

STUDY OBJECTIVE--The aim was to examine causes for non-response in a community survey, and how non-response influences prevalence estimates of some exposure and disease variables, and associations between the variables. DESIGN--This was a cross sectional questionnaire study with two reminder letters. The questionnaire asked for information on smoking habits, occupational airborne exposure and respiratory disorders. SETTING--A random sample of 4992 subjects from the general population aged 15-70 years of Hordaland County, Norway. MAIN RESULTS--The overall response rate was 90%, with a 63% response to the initial letter. The response rates to the first and second reminder letters were 56% and 36% respectively. In 20% of the non-respondents an uncompleted questionnaire was returned with cause for non-response; in two thirds of these the cause for non-response was that the subject was not resident at the mailing address. A home visit to a random sample of 50 urban non-respondents provided further information on 29 subjects. A wrong address at the Central Population Registry and the subject's feeling of lack of personal benefit from a postal survey were the major reasons for non-response. Smokers were late respondents and subjects with respiratory disorders tended to be early respondents. CONCLUSION--The main reasons for non-response were a wrong mailing address and a feeling of lack of personal benefit from responding. Using only the initial letter would have changed the estimated prevalence of smokers from 39% to 35%. Otherwise, the estimated prevalence of the exposure and disease variables as well as the associations between them were only slightly changed after including the respondents to the first and second reminder letters.     

Original Research: Characteristics of Nonrespondents to Questions on Sexual Orientation and Income in a HMO Survey

Objective: The objective of this analysis was to explore variation in item nonresponse to two potentially sensitive questions, sexual orientation and income, among respondents to a large mailed HMO health survey. Method: Multivariate logistic regression analyses were conducted with nonresponse to the items on sexual orientation and income as outcome variables. Predictor variables included gender, age, race/ethnicity, and level of formal education. Results: Overall item nonresponse was 6.0% for the question on sexual orientation and 7.5% for the question on income. Women, older individuals, and people with less formal education were less likely to respond to both questions. Whereas there was no variation in nonresponse to the income question by race, African Americans, Hispanics, and Asians were much more likely than Non-Hispanic Whites to be nonrespondents to the sexual orientation question (odds ratio 1.9, 2.2, and 7.2, respectively). Discussion: This study indicates that although there was relatively low item nonresponse to the question on sexual orientation on a large health survey, special consideration must be given to studies that target older individuals, people of color, and people without a college education.     

Improving response rates through incentive and follow-up: the effect on a survey of physicians' knowledge of genetics.

OBJECTIVES. This study assessed efforts to increase response rates to a mailed physician survey and examined whether, as a result, nonresponse bias was reduced. METHODS. Randomly selected physicians and geneticists were mailed a questionnaire concerning genetics knowledge and attitudes. In the final but not the pilot survey, a $25 incentive and intensive follow-up were used to increase the response rate. RESULTS. The response rate from physicians in the final survey was 64.8% (n = 1140), compared with 19.6% in the pilot test (n = 69). Sample representatives in sociodemographic and practice characteristics was improved by follow-up. Respondents recruited with more difficulty did not differ on the principal outcome variable, genetics knowledge, except on one subscore. Pilot study and final survey respondents did not differ in knowledge. CONCLUSIONS. Although the effect of increased response rates on the principal outcome variable in this study was minimal, this may not be the case for other studies. Every effort should be made to attain as high a response rate as is practical and to establish that respondents are representative of the population being sampled.     

Incentives increased return rates but did not influence partial nonresponse or treatment outcome in a randomized trial

OBJECTIVE: Our aim was to analyze monetary incentives and shortening the questionnaire as means of increasing response rates in a mailed follow-up survey 1 year after inpatient psychotherapeutic treatment. Additionally, effects on partial nonresponse and the assessment of treatment outcome were examined. STUDY DESIGN AND SETTING: In a 2x2 factorial design, a sample of 3,825 patients was randomized to the two following interventions: (1) receiving a prepaid monetary incentive or none; and (2) getting a short or a long questionnaire. Treatment outcome was measured prospectively by a self-assessment instrument for psychopathology. RESULTS: When using incentives, the response rate significantly increased by 7.3% (95% confidence interval [CI] 2.6-11.9%). Receiving a short questionnaire led to an augmentation of the response rate of 3.7% (95% CI 0.9-8.3%), which was not significant. The corresponding odds ratios were significantly increased for monetary incentives (1.36; 95% CI 1.30-1.88), and when abridging the questionnaire (1.15; 95% CI 1.01-1.31). However, partial nonresponse and treatment outcome were independent of the two factors. CONCLUSION: Incentives and a shorter questionnaire led to higher return rates but did not affect partial nonresponse and self-report of treatment outcome in a randomized postal survey.     

Effects of mailed advice on stress reduction among employees in Japan: a randomized controlled trial.

We conducted a randomized controlled trial (RCT) to examine the effects of mailed advice on reducing psychological distress, blood pressure, serum lipids, and sick leave of workers employed in a manufacturing plant in Japan. Those who indicated higher psychological distress (defined as having GHQ scores of three or greater) in the baseline questionnaire survey (n = 226) were randomly assigned to an intervention group or a control group. Individualized letters were sent to the subjects of the intervention group, informing them of their stress levels and recommending an improvement in daily habits and other behaviors to reduce stress. Eighty-one and 77 subjects in the intervention and control groups, respectively, responded to the one-year follow-up survey. No significant intervention effect was observed for the GHQ scores, blood pressure, serum lipids, or sick leave (p > 0.05). The intervention effect was marginally significant for changes in regular breakfasts and daily alcohol consumption (p = 0.09). The intervention effect was marginally significant for the GHQ scores among those who initially did not eat breakfast regularly (p = 0.06). The study suggests that only sending mailed advice is not an effective measure for worksite stress reduction. Mailed advice which focuses on a particular subgroup (e.g., those who do not eat breakfast regularly) may be more effective.     

Selected questionnaire size and color combinations were significantly related to mailed survey response rates

OBJECTIVE: To determine the degree to which mailed survey response rates, response times, and nonresponse bias are affected by questionnaire size and color. STUDY DESIGN AND SETTING: Questionnaires were mailed to a random sample of 2,000 Mayo Clinic patients in one of four size/color "test" groups. One thousand three hundred nine surveys were completed, approximately two-thirds in each group. RESULTS: A small (6 (1/8) x 8 (1/4) in) questionnaire booklet on white paper had a higher response rate (68.4%) than a similarly sized questionnaire on blue paper (62.3%). A large (8 (1/4) x 11 in) questionnaire on white paper had a 62.7% rate, whereas a large, blue questionnaire had a response rate of 68.6%. Median response times did not differ by questionnaire size/color. No evidence of differential nonresponse bias was observed across the four test groups. CONCLUSION: This study supports the use of a small/white questionnaire format advocated by the Total Design Method advanced by Don Dillman at Washington State University. We observed a favorable response rate for a large questionnaire printed on blue paper; however, if time and resources are limited, use of a small/white questionnaire appears preferable.     

A very low response rate in an on-line survey of medical practitioners

OBJECTIVE: To report on the response rate achieved in a survey of medical practitioners and discuss the reasons for it. METHOD: An on-line (internet-based) survey of all 609 registered pharmacotherapy prescribers in Victoria and Queensland; invitations to participate were sent by mail in late April 2007, and one reminder letter in late May 2007. RESULTS: Six hundred and nine invitation letters were mailed, nine were returned to sender, and 52 questionnaires completed, making the overall response rate 52/600 = 8.7%. The response rate in Queensland was 13.2% (16/121), and in Victoria 7.5% (36/479). CONCLUSIONS: Despite utilising sound techniques, our response rate was much lower than those achieved in recent Australian paper-based surveys of medical practitioners. It is possible that the issue being addressed (injecting-related injuries and diseases) was not of high priority for many invitees, leading to reduced response. IMPLICATIONS: On-line surveys are not yet an effective method of collecting data from Australian medical practitioners; researchers should continue to use paper questionnaires for maximum response.     

Side Effects of Diphtheria-Tetanus Toxoid in Adults

During a mass diphtheria-tetanus immunization campaign in November 1975, more than 220,000 doses of diphtheria-tetanus toxoid, adult type were administered to adults throughout Alaska. In Anchorage, where more than 87,000 doses were given, a survey was conducted to determine the frequency of side effects. Postcard questionnaires were mailed to 2,000 randomly selected Anchorage residents; 467 questionnaires were returned by the post office as undeliverable, and 697 questionnaires were completed and returned. A follow-up survey was done of a random sample of the 836 non-responders.Of those responding, 57.8 per cent reported at least one reaction to the toxoids. The most frequent side effects were sore arm (42.7 per cent), swelling at the site of injection (34.8 per cent), and itching (24.2 per cent). Serious side effects occurred less frequently-swelling of the arm below the elbow (1.1 per cent) and abscess or infection (0.7 per cent). Of those vaccinated, 0.5 per cent saw a physician. There were no statistically significant differences in reaction rates by age group, except for sore arms. The jet injector produced more arm swelling at the site of injection, hives, and itching. More women than men reported adverse reactions, especially sore arm, swelling at the site of injection, and itching. Fear of adverse side effects should not preclude mass vaccination of adults. (Am. J. Public Health (69:246-249,1979.)     

A comparison of responses to mailed questionnaires and telephone interviews in a mixed mode health survey

This paper compares respondents to mailed questionnaires with those nonrespondents subsequently interviewed by telephone in a survey of Massachusetts women aged 45-55 years conducted in 1981-1982. This mixed mode approach produced 8,050 responses, giving a response rate of 77%. This rate is similar to rates obtained in many surveys that employed in-person interviews, which are still widely used in health surveys but are increasingly expensive. Telephone respondents differed socioeconomically from mail respondents, suggesting that telephone follow-up of nonrespondents may have reduced nonresponse bias in this survey. Thus, a mixed mode approach may be superior to a mail-only approach with respect to this aspect of data quality. Women responding by mail were more likely to hold professional jobs, to have relatively high household incomes, and to have more years of education. Controlling for these socioeconomic differences did not, however, remove differences in reported health outcomes between mail and telephone respondents. These differences may be explained by less complete recall in the telephone interviews or they may arise from actual differences in health profiles between early (i.e., mail) and late (i.e., telephone) respondents. Although a mixed mode approach may reduce nonresponse bias, more research is required concerning the reasons for response differences between modes and to eliminate any differences caused by problems in data quality.