Contribution of follow-up of nonresponders to prevalence and risk estimates: a Norwegian respiratory health survey

Achieving a high response rate is often expensive and time consuming. Does an extensive survey effort change prevalence estimates and exposure-disease relations? In 1998-1999, the authors conducted a population-based respiratory health survey in two Norwegian counties (Oslo, n = 20,000; Hordaland, n = 5,000) of a random sample of the adult population aged 15-70 years. A postal questionnaire was mailed, with as many as two reminder letters. A 25% random sample of postal nonresponders was contacted by ordinary or cellular telephone. Cumulative response rates after the first mailing, first reminder, second reminder, and telephone follow-up were 42.7%, 60.7%, 68.3%, and 79.9%, respectively. Compared with initial postal responders, responders at later stages were younger, and more were male. Late responders had a lower educational level, were more often smokers, and were occupationally exposed to dusts or gases more frequently. After the authors adjusted for these factors, late responders were found to have less asthma, attacks of breathlessness, and hay fever. Hardly any changes in prevalences and odds ratios were noted when initial responders were compared with all responders. The additional contribution of sending reminder letters and conducting a telephone follow-up to prevalence estimates and the exposure-disease relation was small. A single letter would have produced nearly the same prevalence estimates and risk factor associations.     

Telephone reminders are a cost effective way to improve responses in postal health surveys

STUDY OBJECTIVE: To assess the effectiveness of a telephone reminder in increasing responses to postal surveys and to calculate the differential costs per completed questionnaire. DESIGN: Randomised controlled trial. SETTING: Australian university and rehabilitation medicine practice. PARTICIPANTS: The trial was conducted in 1999 among the 143 non-respondents to a questionnaire about work related neck and upper body disorders. The questionnaire was sent to two Australian female samples: 200 office workers (Sample A) and 92 former rehabilitation medicine patients (Sample B). A reminder letter, another copy of the questionnaire and a final letter were sent at two week intervals. Half of the non-respondents within each sample were randomly selected to receive a telephone reminder just after the second mailout of the questionnaire. All direct costs were calculated. MAIN RESULTS: Responses were significantly higher among those who received the telephone reminder intervention (relative risk 2.54, 95% confidence intervals 1.43 to 4.52). Analysed by intention to phone, 47% of non-respondents in Sample A and 38% in Sample B returned a complete questionnaire after the intervention, compared with 21% and 10%, respectively, in the control groups. For the 112 women (combined samples) who returned completed questionnaires before randomisation, the average cost per respondent was AUD14. There was a higher total cost for the intervention groups (AUD851 versus AUD386 for controls), but the significantly higher number of additional completed responses (31 versus 12) resulted in a 15% lower marginal cost per completed questionnaire in those groups. CONCLUSION: Telephone reminders are cost effective in improving responses to postal surveys.     

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.     

Comparability of skin screening histories obtained by telephone interviews and mailed questionnaires: a randomized crossover study

The comparability of information collected through telephone interviews and information collected through mailed questionnaires has not been well studied. As part of the first phase of a randomized controlled trial of population screening for melanoma in Queensland, Australia, the authors compared histories of skin examination reported in telephone interviews and self-administered mailed questionnaires. A total of 1,270 subjects each completed a telephone interview and a mailed questionnaire 1 month apart in 1999; 564 subjects received the interview first, and 706 received the mailed questionnaire first. Agreement between the two methods was 91.2% and 88.6% for whole-body skin examination by a physician in the last 12 months and the last 3 years, respectively, and 81.9% for whole-body skin self-examination in the last 12 months. Agreement was lower for "any" skin self-examination. Agreement between the two methods was similar regardless of whether the interview or the questionnaire was administered first. Missing data were less frequent for interviews (0.5%) than for mailed questionnaires (3.8%). Costs were estimated at A$9.55 (US$6.21) per completed interview and A$3.01 (US$1.96) per questionnaire. The similarity of results obtained using telephone interviews and mailed questionnaires, coupled with the substantially higher cost of telephone interviews, suggests that self-administered mailed questionnaires are an appropriate method of assessing this health behavior.     

Impact of a postcard versus a questionnaire as a first reminder in a postal lifestyle survey.

STUDY OBJECTIVE--The study aimed to consider the impact of two different types of reminder on response rates and costs in a postal survey. DESIGN--The study was a cross sectional survey. A self-completion lifestyle questionnaire was used. Those who did not respond after the initial mailing were randomly allocated to receive either a postcard or questionnaire as a first reminder. All outstanding non-responders received a questionnaire as a second reminder. SUBJECTS--A representative sample of 698 adults aged 16-70 was used, drawn from a family health services authority register. MAIN RESULTS--Postcard reminders were as effective as questionnaire reminders in increasing response whether one or two reminders are sent. The costs per response were calculated. Two questionnaires as reminders were found to be 1.7 times more expensive than a postcard plus questionnaire. Including the initial mailing, the cost per response using all questionnaires was 1.3 times the cost when a postcard was used for the first reminder. CONCLUSIONS--To increase the response to a postal survey effectively and economically, two reminders should be sent--first a postcard and then a questionnaire.     

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.     

Postal surveys of physicians gave superior response rates over telephone interviews in a randomized trial

BACKGROUND AND OBJECTIVES: To compare general practitioner (GP) response to a telephone interview with response to a postal survey with three reminders in a randomized controlled trial. METHODS: GPs were randomly assigned to either a telephone interview or a postal survey. GPs in the telephone group were mailed a letter of invitation and asked to undertake a telephone interview. GPs in the postal group were mailed a letter of invitation and questionnaire. Non-responders were sent up to three reminders, the final by registered post. Response rates were calculated for each group. RESULTS: 416 GPs were randomized to the telephone interview and 451 to the postal survey. Eighty-six in the telephone group and 30 in the postal were ineligible. One hundred thirty-four GPs completed the telephone interview with a response rate of 40.6% (95% confidence interval [CI]: 35.3%, 46.1%). Two hundred fifty-two GPs completed the postal survey with a response rate of 59.9% (95%CI: 55.0%, 64.6%). The difference in response was 19.3% (95%CI: 12.2%, 26.3%). CONCLUSIONS: These results show that postal surveys with three reminders can have superior response rates compared with a telephone interview.     

Effect of survey instrument on participation in a follow-up study: a randomization study of a mailed questionnaire versus a computer-assisted telephone interview

ABSTRACT: BACKGROUND: Many epidemiological and public health surveys report increasing difficulty obtaining high participation rates. We conducted a pilot follow-up study to determine whether a mailed or telephone survey would better facilitate data collection in a subset of respondents to an earlier telephone survey conducted as part of the National Birth Defects Prevention Study. METHODS: We randomly assigned 392 eligible mothers to receive a self-administered, mailed questionnaire (MQ) or a computer-assisted telephone interview (CATI) using similar recruitment protocols. If mothers gave permission to contact the fathers, fathers were recruited to complete the same instrument (MQ or CATI) as mothers. RESULTS: Mothers contacted for the MQ, within all demographic strata examined, were more likely to participate than those contacted for the CATI (86.6% vs. 70.6%). The median response time for mothers completing the MQ was 17 days, compared to 29 days for mothers completing the CATI. Mothers completing the MQ also required fewer reminder calls or letters to finish participation versus those assigned to the CATI (median 3 versus 6), though they were less likely to give permission to contact the father (75.0% vs. 85.8%). Fathers contacted for the MQ, however, had higher participation compared to fathers contacted for the CATI (85.2% vs. 54.5%). Fathers recruited to the MQ also had a shorter response time (median 17 days) and required fewer reminder calls and letters (median 3 reminders) than those completing the CATI (medians 28 days and 6 reminders). CONCLUSIONS: We concluded that offering a MQ substantially improved participation rates and reduced recruitment effort compared to a CATI in this study. While a CATI has the advantage of being able to clarify answers to complex questions or eligibility requirements, our experience suggests that a MQ might be a good survey option for some studies.     

Evaluation of a heart disease survey and education program for general practitioners

Abstract: In 1989 we mailed a questionnaire to all 461 general practitioners (GPs) identified as currently practising in the Eastern Metropolitan Health Region of Sydney. This was the first phase of a program to assess, amplify and reassess GPs' knowledge of the risk factors for heart disease and measure their attitudes and beliefs about their role in the prevention of cardiovascular disease. The second phase was an education program designed to meet the needs identified by the first questionnaire. Phase three was a postintervention questionnaire. Fifty-six per cent (260/461) responded to the first questionnaire. This follow-up group were mailed the second questionnaire, to which 52 per cent (135/260) responded. Thirty per cent of the original sample (139/461) attended the education program and 30 per cent (79/260) of the follow-up group did so. At baseline, the respondents' level of risk factor knowledge was good, but after the education program there was still a large gap between what they said they knew and the amount of advice they said they would give to patients. The only significant increase in the amount of advice after the intervention was to ‘control blood pressure’. This applied whether the GP had participated in the intervention or not. When GPs were asked how often in the last month they had actually given advice to reduce cardiovascular disease risk, program attenders reported offering it more frequently than nonattenders. We also attempted to determine whether any particular demographic characteristics could predict respondents to the questionnaires and/or the educational program.     

Differential effectiveness of telephone prompts by medical and nonmedical staff in increasing survey response rates: a randomised trial

Abstract: We conducted a randomised trial to determine the differential effectiveness of a telephone prompt by a medical researcher compared with a nonmedical research assistant in improving response rates of general practitioners to a survey and to compare personnel costs. A national random sample of Australian general practitioners was allocated randomly to two intervention groups. In advance of a self–administered questionnaire, Group A (n = 184) received a telephone prompt by a medical researcher and Group B (n = 189) a prompt by an experienced nonmedical research assistant. Other aspects of survey administration were identical for both groups. The five–month cumulative response rate obtained by the medical researcher (81 per cent) was not significantly different from that of 72 per cent obtained by the research assistant ( X ²= 3.3, 1 df, P = 0.07). For Group A, 279 telephone calls, consuming 23 hours 15 minutes, were made. Group B required more calls (384) and more time (32 hours). Using the relevant award pay scales, the estimated personnel costs for each group were $631 and $601 respectively. We conclude that an experienced nonmedical research assistant is as effective as a medical practitioner in administering telephone prompts to enhance survey response rates, although savings are not necessarily made.     

Participation in breast cancer screening: randomised controlled trials of doctors' letters and of telephone reminders

Abstract: The study used a randomised controlled trial to find out whether supporting letters from general practitioners accompanying the invitations from a screening centre affected participation in a population-based breast cancer screening program for women aged 50 to 64. A further randomised controlled trial compared the effect of postal reminders with telephone reminders for women who did not respond to an initial invitation to participate in the program. There were 482 women in the first trial and 641 in the second. Excluding women who were ineligible or could not be contacted, participation in screening was 71 per cent in the group which received letters from their general practitioners compared with 62 per cent in the group which did not receive letters (P = 0.059). In the group that received letters, 56 per cent were screened without a reminder compared with 43 per cent of the group that did not receive letters (P = 0.01). Fewer women who received letters from their general practitioners declined the invitation to be screened (P = 0.048). In the second trial, there was no difference in participation between the group receiving telephone reminders and the group receiving postal reminders. As in breast cancer screening programs in other countries, general practitioner endorsement of invitations increased participation in breast cancer screening. Postal reminders were as effective as telephone reminders in encouraging women who did not respond to an initial invitation to participate in screening.     

医院患者就医满意度问卷调查法和电话调查法的差异化比较

目的：研究问卷调查和电话调查两种方法调查患者满意度的优劣。方法分别采用问卷调查法和电话调查法对出院患者就医满意度进行调查,比较两种方法每小时的调查人数和患者的满意度。结果问卷调查组每小时调查的患者人数为8人,电话调查组每小时调查的患者人数为15人;电话随访组病人满意度为90.73%,问卷调查组患者满意度为95.61%。两种调查方式比较,每小时的调查人数和患者的满意度差异均有统计学意义（P 〈0.01）。结论电话随访调查法优于问卷调查法。     

Increasing Colorectal Cancer Screening in an Overdue Population: Participation and Cost Impacts of Adding Telephone Calls to a FIT Mailing Program

Many people who live in rural areas face distance barriers to colonoscopy. Our previous study demonstrated the utility of mailing fecal immunochemical tests (FIT) to average risk patients overdue for colorectal cancer (CRC screening). The aims of this study were to determine if introductory and reminder telephone calls would increase the proportion of returned FITs as well as to compare costs. Average risk patients overdue for CRC screening received a high intensity intervention (HII), which included an introductory telephone call to see if they were interested in taking a FIT prior to mailing the test out and reminder phone calls if the FIT was not returned. This HII group was compared to our previous low intensity intervention (LII) where a FIT was mailed to a similar group of veterans with no telephone contact. While a higher proportion of eligible respondents returned FITs in the LII (92 vs. 45 %), there was a much higher proportion of FITs returned out of those mailed in the HII (85 vs. 14 %). The fewer wasted FITs in the HII led to it having lower cost per FIT returned ($27.43 vs. $44.86). Given that either intervention is a feasible approach for patients overdue for CRC screening, health care providers should consider offering FITs using a home-based mailing program along with other evidence-based CRC screening options to average risk patients. Factors such as location, patient population, FIT cost and reimbursement, and personnel costs need to be considered when deciding the most effective way to implement FIT screening.     

The effect of telephone reminders on attendance in respiratory outpatient clinics

INTRODUCTION: Patient non-attendance is an area of concern for all health care providers. A randomized controlled trial was undertaken to investigate whether reminder telephone calls improved attendance at respiratory outpatient clinics in the English National Health Service (NHS). METHODS: Patients were randomly allocated into one of two groups, either telephone reminder group or usual care. The telephone reminder group received a reminder telephone call between 9 am and 5 pm during the week prior to their appointment. Attendance and demographic information (age, sex, diagnosis and home postcode) were recorded. RESULTS: A total of 504 patients were recruited, 258 patients were allocated to the control group and 246 patients were allocated to the telephone reminder group. Fifty-eight percent of the patients allocated to the telephone reminder group were not contactable. Within the telephone reminder group, of the 104 patients who could be contacted, 86% attended. There was a significant 15% increase in attendance in the contacted group (n = 104) when compared both with the control group (71%, n = 258) and with the patients who could not be contacted (68%, n = 142) (P = 0.007; P = 0.004). It was estimated that the cost of telephoning 200 patients could be offset by preventing one non-attendance. CONCLUSION: Routine telephoning of outpatients should become standard practice if reducing non-attendance is thought to be desirable, but general practitioner (GP) referral letters and hospital records of current hospital outpatients need to include an up-to-date telephone number. Consideration should be given to 'out-of-hours' reminder calls to maximize the contact rate.     

National survey of hospital infection control organization in Italian public hospitals

A questionnaire was mailed to 1073 Italian public hospitals in an attempt to find out if infection control programmes existed, the type of programme used and available resources. After two attempts a total of 54.9 per cent of the hospitals responded to the request and of these 16.1 per cent claimed to have an infection control programme. Sixty-six per cent of the hospitals who have a control programme also have a system of continuous surveillance whilst the remainder investigated epidemics only. Infection control programmes were encountered most frequently in paediatrics, obstetrics and surgical departments. The organisms most often surveyed were the salmonellas, other types of enterobacteria, staphylococci and streptococci.     

Properties of the Picker Patient Experience questionnaire in a randomized controlled trial of long versus short form survey instruments

BACKGROUND: The purpose of this study was to compare the performance of the 15-item Picker Patient Experience questionnaire (PPE-15) when embedded in a short form instrument as compared with a longer form measure. METHODS: A postal questionnaire survey of patients recently discharged from two hospital trusts was carried out. Patients were randomized to receive the PPE-15 in either a four-page or a 12-page survey instrument. RESULTS: A total of 1445 questionnaires were mailed to patients in either four- or 12-page formats. A total of 949 (65.67 per cent) forms were returned. No difference in response rate was found between the two versions of the questionnaire. Item completion and psychometric properties of the PPE-15 were not found to differ significantly between the two arms of the trial. CONCLUSION: In this survey the length of questionnaire in which the PPE-15 was embedded had no impact in terms of response rate or data quality. Consequently, the results suggest that length of questionnaire, up to the 108 items included in the 12-page survey, is unlikely to adversely affect results on the PPE-15.     

Cervical cancer screening for hospital inpatients: report of an intervention study

A pilot study of a cervical cancer screening service was carried out at a major teaching hospital in Perth. The service, for women inpatients aged 20 to 69 years, was staffed by a women's health nurse. The effect of providing the service (service) was compared with giving a leaflet on Pap smears to eligible women (education) and with no intervention (control). Of 517 women in the service group, 184 (36 per cent) needed a Pap smear and were well enough to be offered screening; only 29 of 184 (16 per cent) refused and 132 of 184 (72 per cent) were screened. Of those screened, 29 per cent had never had a Pap smear. Information on women in the education and control groups was obtained by mailed questionnaire. Of the eligible women in the service group, 72 per cent accepted screening in hospital, but only 24 per cent of eligible women in the education group and 20 per cent in the control group reported having a Pap smear in the four months since leaving hospital. The service group showed a very large effect relative to the control group (odds ratio (OR) 17.71, 95 per cent confidence interval (CI) 10.05 to 31.22), but there was no significant difference between the education and control groups. Other significant variables in the logistic regression model were age, marital status, and sex of the woman's general practitioner. The effect of offering the service was greater for women over 50 (OR 51.51, CI 19.01 to 139.60) A hospital-based cervical screening service provides an important opportunity for screening women who are not being reached by other services. (Aust J Public Health 1995; 19: 288–93)     

Reliability and validity of a modified self‐administered version of the Active Australia physical activity survey in a sample of mid‐age women

Objective: To assess the test‐retest reliability and validity of a modified self‐administered version of the Active Australia physical activity survey. Methods: One hundred and fifty‐nine mid‐age women (54–59 years) completed a mailed physical activity questionnaire before recording daily pedometer step counts for seven consecutive days. A random subsample (n=44) also wore an accelerometer during this period. Participants then completed the physical activity questionnaire again. Spearman's ρ and per cent agreement were used to assess test‐retest reliability. Self‐reported physical activity data (time 2) were compared with pedometer and accelerometer data using box plots and Spearman's correlations to assess validity. Results: Median time between surveys was 13 days. Median frequency and duration of moderate and vigorous physical activity were the same at both surveys, but median walking frequency was slightly higher at time 2 than time 1. Reliability coefficients for frequency/time in each domain of physical activity ranged from 0.56–0.64 and per cent agreement scores ranged from 40% to 65% for the physical activity categories; agreement was 76% for ‘meeting guidelines’. Correlations (p) between self‐reported physical activity and 1) weekly pedometer steps and 2) accelerometer data for duration of at least moderate intensity physical activity were 0.43 and 0.52 respectively. Conclusions: The measurement properties of this modified self‐administered physical activity survey are similar to those reported for the original computer assisted telephone interview survey. Implications: This modified version of the Active Australia survey is suitable for use in self‐administered format.     

The effect of a monetary incentive in increasing the return rate of a survey to family physicians

The barrage of requests family physicians receive to complete mail surveys often results in physicians who are unwilling, or unable due to time constraints, to complete each survey they receive. Thus, to obtain an acceptable response rate, state-of-the-art mail survey techniques must be used. This article reports the results of the use of a modest ($1) monetary incentive to increase a survey response rate. A random sample of 600 American Academy of Family Physicians members were mailed a survey of firearm safety counseling; half received a $1 incentive whereas the remaining half served as a control group. The response rate in the incentive group was 63% compared to 45% in the control group [chi 2 (1, N = 251) = 16.0, p < .001]. Further, the use of the incentive appears to be more cost-effective than a third follow-up (postcard reminder) mailing.     

Evaluation of the New South Wales Cancer Council Pap Test Reminder Service

Abstract: This study aimed to assess the effect of reminder letters on Pap test rates for women enrolled on the New South Wales Cancer Council Pap Test Reminder Service and to identify predictors of response to the letter. Ten weeks after they had received their reminder letter a questionnaire was sent to 3086 women. It was completed by 1525 (49 percent) women, of whom 1393 (91 percent) said they had received their reminder letter. Of these 1393, 48 per cent (95 per cent confidence interval 46 per cent to 51 per cent) reported having had a Pap test within 10 weeks of the reminder letter arriving. The proportion of women having a Pap test in response to the reminder letter did not differ by age, region of residence or language spoken at home. Women were less likely to have had a Pap test if they did not know how they were enrolled, were of low socioeconomic status or had some tertiary education. Women on the reminder service have 15-month rescreening rates at least 9 per cent higher than other women in New South Wales; for women aged 50 to 69 in nonmetropolitan areas the increase is estimated at 19 per cent. Reminder services may be a cost-effective way to increase Pap test rescreening rates. Reminder services need accurate records and to follow up changes in address and date of next test.