Increasing response rates of gynaecologists to a survey: a randomised trial of telephone prompts

Abstract: This study used a randomised controlled trial to evaluate the effectiveness of telephone prompts to increase the response rate of gynaecologists to a survey. A nine-page questionnaire about management of women with abnormal Pap smears was mailed to Fellows of the Royal Australian College of Obstetricians and Gynaecologists. A random sample was contacted in advance by telephone, and nonrespondents received a telephone reminder 14 days after the initial mail-out. The control group was mailed questionnaires and a reminder letter conventionally. On Day 25, nonresponders in both groups were mailed a second questionnaire. Of the intervention group, 84 per cent responded to the survey compared to 69 per cent of the control group (P = 0.005). A telephone call in anticipation of a mailed questionnaire is highly recommended.     

A prenotification letter increased initial response,whereas sender did not affect response rates

ObjectiveTo find ways to improve response rates of medical and health surveys. We investigated whether a prenotification letter instead of a second reminder and varying senders of the questionnaires would affect response rates.Study Design and SettingWe present the results of two studies. In the first study, four groups were compared that either received a prenotification letter (group 1 and 2) or a second reminder letter (group 3 and 4); received the questionnaire from either a research institute (group 1 and 3) or a health insurance company (HIC; group 2 and 4). In the second study, we compared two groups that received the questionnaire sent by either a HIC or a hospital. Response rates, response speed, respondent characteristics, item nonresponse, and mean scores on quality aspects and global ratings were compared.ResultsResponse rates did not differ significantly between groups. Prenotification groups returned their questionnaires faster. No other significant differences were found for response speed, respondent characteristics, item nonresponse, or mean scores.ConclusionA prenotification letter does only increase initial response speed and does not increase total response rates. A prenotification letter should be considered when quick response is desirable. Varying senders had no effect on response rates.     

Participation in a mail survey: role of repeated mailings and characteristics of nonrespondents among recent mothers

This study analysed the characteristics of respondent and nonrespondent mothers at each stage of a survey procedure, from a initial questionnaire to a reminder letter and two repeated mailings. Of 938 mothers of liveborn children who, while maternity inpatients, received a questionnaire and information about a mail survey to follow 2 months later, 828 completed and returned the initial questionnaire, 708 agreed to participate in the mail survey and were sent the mail questionnaire, and 612 finally completed and returned the questionnaire at 2 months. There were differences between respondents and non-respondents for socio-demographic factors at each stage of the process. The final response rate to the mail questionnaire was higher among mothers who were younger, were breast feeding, and had more education, an occupation and fewer children. The characteristics of late respondents were intermediate between those of early to middle respondents and nonrespondents for age, educational level, breast feeding and occupation. Maternal and infant health varied only slightly according to response status. Repeated mailings increased response and diminished selection. A mail questionnaire after contact in a maternity ward is a cost-effective means of gathering data about a large sample of recent mothers and their children.     

Increasing response rates in physicians'' mail surveys: an experimental study.

It is becoming increasingly difficult to obtain high response rates in physicians' mail surveys. In 1983-84, we tested the effectiveness of two techniques among 604 Quebec physicians who had not responded to an initial letter. A handwritten thank you note at the bottom of the letter accompanying the questionnaire and a more personalized mailout package increased response rates by 40.7 per cent and 53.1 per cent, respectively, compared to control groups.     

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.     

Oral fluid collection by post for viral antibody testing

BACKGROUND: The objective of this study was to estimate the prevalence of hepatitis B virus exposure (HBV) in the population of the Republic of Ireland, by using oral fluid (saliva) collection by post for hepatitis B anti-core antibody (anti-HBc). This paper discusses the methodological approach used and the strategies that were adopted to improve response rates. METHODS: The sampling frame used was the Register of Electors for Irish parliamentary elections. A multistage stratified cluster sample was taken, and a total of 962 households were selected nationally. A four-letter approach was employed for sample collection. Households received an initial letter outlining the purpose of the study. This was followed by a letter containing six swabs for oral fluid collection, along with easy-to-follow instructions. Non-respondents received two reminder letters, and were also telephoned where possible. A telephone helpline was provided. All testing was anonymous and unlinked. RESULTS: The study achieved a good household response rate (60.4%), and more than 98% of the 1738 specimens received were suitable for testing. The prevalence of anti-HBc in the Irish population was estimated to be 0.51%. The observed design effect was 1.29. DISCUSSION: From a review of the literature, this is the first study where a representative sample of a national population was asked to self-collect oral fluid samples and return these by post for serological testing. The technique may have many future applications in epidemiological research.     

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.     

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.     

Reducing questionnaire length did not improve physician response rate: a randomized trial

ObjectivesTo examine the effect of reducing questionnaire length on the response rate in a physician survey.Study Design and SettingA postal four double-page questionnaire on end-of-life decision making was sent to a random sample of 1,100 general practitioners, 400 elderly care physicians, and 500 medical specialists. Another random sample of 500 medical specialists received a shorter questionnaire of two double pages. After 3 months and one reminder, all nonresponding physicians received an even shorter questionnaire of one double page.ResultsTotal response was 64% (1,456 of 2,269 eligible respondents). Response rate of medical specialists for the four double-page questionnaire was equal to that of the two double-page questionnaire (190 and 191 questionnaires were returned, respectively). The total response rate increased from 53% to 64% after sending a short one double-page questionnaire (1,203–1,456 respondents).ConclusionThe results of our study suggest that reducing the length of a long questionnaire in a physician survey does not necessarily improve response rate. To improve response rate and gather more information, researchers could decide to send a drastically shortened version of the questionnaire to nonresponders.     

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.     

An experiment of mailing physician surveys on two different issues in joint or separate mail

High response rates from physicians play an important role in obtaining valid data on practice patterns. We wanted to know whether two questionnaires (one on hernia surgery and one on perioperative pain management) should better be sent out in one letter or two separate letters. We randomized 2,393 surgeons who received the two questionnaires either in one letter or by separate mail, in two letters, at a time interval of 4 weeks. The response rate for the separate mailout was not significantly higher when compared to the joint mailout. The differences were 3.3% (95%-CI -0,4% to 7.1%) and 2.2% (95%-CI -1,4% to 5.9%) for the two surveys. Due mainly to higher postage costs, the costs per response were doubled in the separate mailout group (5.85 Euro versus 2.93 Euro). Sending out two surveys separately seems to have only little effect on the response rates.     

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.     

Assessing delivery practices of mothers over time and over space in Uganda, 2003–2012

The issue of poor response rates to population surveys has existed for some decades, but few studies have explored methods to improve the response rate in follow-up population cohort studies. A sample of 100,000 adults from the 45 and Up Study, a large population cohort in Australia, were followed up 3.5 years after the baseline cohort was assembled. A pilot mail-out of 5000 surveys produced a response rate of only 41.7 %. This study tested methods of enhancing response rate, with three groups of 1000 each allocated to (1) receiving an advance notice postcard followed by a questionnaire, (2) receiving a questionnaire and then follow-up reminder letter, and (3) both these strategies. The enhanced strategies all produced an improved response rate compared to the pilot, with a resulting mean response rate of 53.7 %. Highest response was found when both the postcard and questionnaire reminder were used (56.4 %) but this was only significantly higher when compared to postcard alone (50.5 %) but not reminder alone (54.1 %). The combined approach was used for recruitment among the remaining 92,000 participants, with a resultant further increased response rate of 61.6 %. Survey prompting with a postcard and a reminder follow-up questionnaire, applied separately or combined can enhance follow-up rates in large scale survey-based epidemiological studies.     

Patient views on reminder letters for influenza vaccinations in an older primary care patient population: a mixed methods study

OBJECTIVES: To explore the perspectives of older adults on the acceptability of reminder letters for influenza vaccinations. METHODS: We randomly selected 23 family physicians from each Family Health and Primary Care network participating in a demonstration project designed to increase the delivery of preventive services in Ontario. From the roster of each physician, we surveyed 35 randomly selected patients over 65 years of age who recently received a reminder letter regarding influenza vaccinations from their physician. The questionnaires sought patient perspectives on the acceptability and usefulness of the letter. We also conducted follow-up telephone interviews with a subgroup of respondents to explore some of the survey findings in greater depth. RESULTS: 85.3% (663/767) of patients completed the questionnaire. Sixty-five percent of respondents recalled receiving the reminder (n=431), and of those, 77.3% found it helpful. Of the respondents who recalled the letter and received a flu shot (n=348), 11.2% indicated they might not have done so without the letter. The majority of respondents reported that they would like to continue receiving reminder letters for influenza vaccinations (63.0%) and other preventive services (77.1%) from their family physician. The interview participants endorsed the use of reminder letters for improving vaccination coverage in older adults, but did not feel that the strategy was required for them personally. CONCLUSIONS: The general attitude of older adults towards reminder letters was favourable, and the reminders appear to have contributed to a modest increase in influenza vaccination rates.     

Do incentives, reminders or reduced burden improve healthcare professional response rates in postal questionnaires? two randomised controlled trials

ABSTRACT: BACKGROUND: Healthcare professional response rates to postal questionnaires are declining and this may threaten the validity and generalisability of their findings. Methods to improve response rates do incur costs (resources) and increase the cost of research projects. The aim of these randomised controlled trials (RCTs) was to assess whether 1) incentives, 2) type of reminder and/or 3) reduced response burden improve response rates; and to assess the cost implications of such additional effective interventions. METHODS: Two RCTs were conducted. In RCT A general dental practitioners (dentists) in Scotland were randomised to receive either an incentive; an abridged questionnaire or a full length questionnaire. In RCT B non-responders to a postal questionnaire sent to general medical practitioners (GPs) in the UK were firstly randomised to receive a second full length questionnaire as a reminder or a postcard reminder. Continued non-responders from RCT B were then randomised within their first randomisation to receive a third full length or an abridged questionnaire reminder. The cost-effectiveness of interventions that effectively increased response rates was assessed as a secondary outcome. RESULTS: There was no evidence that an incentive (52% versus 43%, Risk Difference (RD) -8.8 (95%CI [MINUS SIGN]22.5, 4.8); or abridged questionnaire (46% versus 43%, RD [MINUS SIGN]2.9 (95%CI [MINUS SIGN]16.5, 10.7); statistically significantly improved dentist response rates compared to a full length questionnaire in RCT A. In RCT B there was no evidence that a full questionnaire reminder statistically significantly improved response rates compared to a postcard reminder (10.4% versus 7.3%, RD 3 (95%CI [MINUS SIGN]0.1, 6.8). At a second reminder stage, GPs sent the abridged questionnaire responded more often (14.8% versus 7.2%, RD [MINUS SIGN]7.7 (95%CI [MINUS SIGN]12.8, -2.6). GPs who received a postcard reminder followed by an abridged questionnaire were most likely to respond (19.8% versus 6.3%, RD 8.1%, and 9.1% for full/postcard/full, three full or full/full/abridged questionnaire respectively). An abridged questionnaire containing fewer questions following a postcard reminder was the only cost-effective strategy for increasing the response rate ([POUND SIGN]15.99 per response). CONCLUSIONS: When expecting or facing a low response rate to postal questionnaires, researchers should carefully identify the most efficient way to boost their response rate. In these studies, an abridged questionnaire containing fewer questions following a postcard reminder was the only cost-effective strategy. An increase in response rates may be explained by a combination of the number and type of contacts. Increasing the sampling frame may be more cost-effective than interventions to prompt non-responders. However, this may not strengthen the validity and generalisability of the survey findings and affect the representativeness of the sample.     

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.     

Patient reminder letters to promote annual mammograms: a randomized controlled trial

BACKGROUND: This study assessed the effects of a reminder letter from a physician (relative to a mammography facility letter or no letter) on appointment compliance among women 50-74 years of age due for an annual screening mammogram. METHODS: A total of 1,562 women were randomly as signed to the groups. Each Group 1 subject received a reminder letter from her physician, each Group 2 subject received a reminder letter from her mammography facility, and Group 3 served as a control group. RESULTS: The return rates for Groups 1, 2, and 3 were 47.7, 46.6, and 28.3%, respectively; the overall difference was significant using a chi(2) analysis (P < 0.001). Bonferroni pairwise comparisons indicated no difference between Groups 1 and 2 but significant differences (P < 0.001) between Group 3 and the other two groups. Logistic regression indicated that relative to Group 3, the adjusted odds of returning for Groups 1 and 2 were 2.37 and 2.24, respectively. CONCLUSIONS: Mammography providers and their patients likely will benefit from in-reach reminder systems. Physicians who do not use reminder systems should refer their patients to facilities that use these systems.     

Increasing response to a postal survey of sedentary patients - a randomised controlled trial [ISRCTN45665423]

Background

A systematic review identified a range of methods, which can influence response rates. However, analysis specific to a healthcare setting, and in particular, involving people expected to be poor responders, was missing, We examined the effect of pre-warning letters on response rates to a postal survey of sedentary patients whom we expected a low rate of response.

Methods

Participants were randomised to receive a pre-warning letter or no pre-warning letter, seven days before sending the main questionnaire. The main questionnaire included a covering letter and pre-paid return envelope. After seven days, non-responders were sent a reminder letter and seven days later, another reminder letter with a further copy of the questionnaire and return envelope.

Results

627 adults, with a mean age of 48 years (SD 13, range 18 to 78) of whom 69.2% (434/627) were women, were randomised. 49.0% (307/627) of patients were allocated to receive a pre-warning letter and 51.0% (320/627) no pre-warning letter, seven days in advance of posting the main questionnaire. The final response rate to the main questionnaire was 30.0% (92/307) amongst those sent a pre-warning letter and 20.9% (67/320) not sent a pre-warning letter, with an adjusted odds ratio of 1.60 (95% CI 1.1, 2.30).

Conclusions

The relatively low cost method of sending a pre-warning letter had a modest impact on increasing response rates to a postal questionnaire sent to a group of patients for whom a low response rate was anticipated. Investigators should consider incorporating this simple intervention when conducting postal surveys, to reduce the potential for nonresponse bias and to increase the study power. Methods other than postal surveys may be needed however when a low response rate to postal surveys is likely.     

Does a deadline improve men's participation in self-administered health surveys? A randomized controlled trial in general practice

BACKGROUND: Self-administered questionnaires are commonly used in experimental studies to elicit quality of life or other outcomes. Hence, achieving an acceptable level of follow-up from patients is critical to minimizing bias. Many methods for maximizing follow-up remain untested. It is also unclear what level of follow-up is required to prevent bias being introduced. METHODS: We recruited 246 men from general practice surgeries in Sydney, Australia. These 246 men were randomized to receive a covering letter with their follow-up questionnaire either advising of a deadline to reply (Deadline, n = 126) or a standard letter without a deadline (No Deadline, n = 120). Four standardized reminder prompts subsequently were administered. We calculated interim response rates and the final proportion of follow-up questionnaires received according to group. We also compared scores on two main outcomes, namely, knowledge and decisional conflict at each time when reminder prompts were administered. RESULTS: One hundred and twelve (88.9%) men in the Deadline group returned their follow-up questionnaires compared with 102 (85.0%) men in the No Deadline group. This difference was not statistically significant [odds ratio = 1.41, 95% confidence interval (CI) = 0.67-2.99; p = 0.36]. Time to response also was not significantly affected by cover letter received (hazard ratio = 0.96; 95% CI = 0.73-1.25; p = 0.76). Results of the original RCT were similar in terms of direction and effect size at all times irrespective of when reminder prompts were administered. CONCLUSION: The addition of a deadline adds no further impact in improving response rates from male patients compared with an unspecified letter. Despite the accepted wisdom that higher response protects against bias, differences in outcomes were consistent throughout the post-test data collection period.     

Does length of questionnaire matter? A randomised trial of response rates to a mailed questionnaire

OBJECTIVE: To assess whether length of questionnaire affects response rates. METHODS: A quasi-randomised trial of women aged 70 years and over in a general practice in England. Three questionnaires of different lengths: a clinical questionnaire (four pages); the same questionnaire plus the EuroQol (five pages); the same questionnaire plus the SF-12 (seven pages). The impact of length on the proportion of returned questionnaires and item completion rates was assessed. RESULTS: In total, 847 questionnaires were mailed; response rates were 49%, 49% and 40% to the short, medium and long questionnaires, respectively. This difference was statistically significant when the short questionnaire was compared against the longest instrument (9% difference; 95% confidence interval (CI) of difference = 0.3% to 16.6%). Item completion rates for the clinical questionnaire did not differ. Respondents did not differ in age or self-reported health status between the three groups. CONCLUSIONS: Increasing the length of a questionnaire from five to seven pages reduces response rates from women aged 70 years and over. However, lengthening a questionnaire does not seem to affect the quality of responses to questions near the front of the questionnaire.