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.     

Enclosing a pen with a postal questionnaire can significantly increase the response rate

BACKGROUND AND OBJECTIVES: It is important to maximize response rates to postal questionnaires. We compared the impact of three low-cost interventions on response rates. METHODS: A 2 x 2 x 2 factorial trial was conducted, nested within TOMBOLA (Trial Of Management of Borderline and Other Low-grade Abnormal smears). Three interventions were evaluated: (1) enclosing a TOMBOLA-branded pen with the questionnaire (as opposed to no pen); (2) sending the questionnaires by first class post (as opposed to second class); and (3) enclosing a preaddressed return envelope on which there was a second class postage stamp (rather than a freepost business-reply envelope). Nine hundred thirty women, aged 20-59 years, due to receive a TOMBOLA psychosocial questionnaire by post during June-August 2003 were randomized. RESULTS: Enclosing a pen resulted in a statistically significant 7.0% increase in the cumulative proportion of questionnaires returned (from 61.5 to 68.5%; P = .002). The adjusted odds of response was significantly raised (odds ratio [OR] = 1.38, 95% confidence interval [CI] 1.04-1.82). Neither first class post nor providing a stamped envelope had a significant impact on response. There were no interactions between the interventions. CONCLUSIONS: Enclosing a pen with a questionnaire can significantly increase response. This low-cost strategy was effective against a background of "good practice" with regard to the administration of postal questionnaires.     

Prenotification had no additional effect on the response rate and survey quality: a randomized trial

ObjectivesTo determine the effect of prenotification package on survey quality, including response rates, response time, percentage of nonresponse items, and cost.Study Design and SettingParticipants were randomized into two groups. In the first round mailing, participants in prenotification group received a prenotification package, whereas direct questionnaire mailing group participants received a questionnaire with prepaid return envelope only. In the second round mailing, both groups received the questionnaires. The trial was integrated into a study among 35–65-year-old female nurses in Hong Kong.ResultsA total of 367 nurses were included in the trial. A total of 362 mails were successfully delivered. The initial response rate in the first round mailing were 8.79% and 8.89% for prenotification and direct questionnaire mailing groups, respectively. After the second round mailing, the final response rate in prenotification and direct questionnaire mailing groups were 17.58% and 17.22%, respectively; no significant difference was found between the groups. There were no differences with respect to percentage of nonresponse items or response time, but the cost of prenotification group was HK$ 15.11 per response higher than direct mailing group.ConclusionPrenotification had no additional effect on the response rate and other survey quality compared with direct questionnaire mailing in a Hong Kong population.     

A mail survey of United States hematologists and oncologists: a comparison of business reply versus stamped return envelopes

Mailed surveys are a popular means of obtaining data on large populations. In July 1999 a mail survey was conducted among 3000 randomly selected members of the American Society of Hematology to assess their approach to diagnosis and treatment of polycythemia vera. Because the researchers and the study population are members of the same professional organization with a vested interest in the results, we anticipated that the advantages of return stamped postage seen in previous studies would be less significant. The response rate for stamped return envelopes was 38% versus 32% for business reply envelopes. This statistically significant difference (P =.0005) of six percentage points is comparable to previous research. Excluding labor, the total cost per returned survey was $2.62 for business reply envelopes versus $1.82 for stamped return envelopes. We conclude that stamped return envelopes are a more effective and cost-efficient means of procuring data from physician specialists.     

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.     

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.     

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.     

Effects of incentives and prenotification on response rates and costs in a national web survey of physicians

Little is known about what strategies are cost-effective in increasing participation among physicians in surveys that are conducted exclusively via the web. To assess the effects of incentives and prenotification on response rates and costs, general internists (N = 3,550) were randomly selected from the American Medical Association (AMA) Masterfile and assigned to experimental groups that varied in the amount of a promised incentive (none, entry into a $200 lottery, $50, or $100) and prenotification (none, prenotification letter only, or prenotification letter containing a $2 preincentive). Results indicated that the response rates were highest in the groups promised $100 and $50, respectively. While the postal prenotification letter increased response rates, the inclusion of a small token $2 preincentive had no effect on participation. Further, unlike mail surveys of physicians, the $2 preincentive was not cost-effective. Among physicians, larger promised incentives of $50 or $100 are more effective than a nominal preincentive in increasing participation in a web-only survey. Consistent with prior research, there was little evidence of nonresponse bias among the experimental groups.     

Use of patient reminder letters to promote cancer screening services in women: A population-based study in Wisconsin.

BACKGROUND: Patient reminder letters are an effective method of promoting cancer screening services in women; however, information on their actual use in a population setting is lacking. METHODS: Data were obtained from a population-based, random digit dial telephone survey of 896 adult women living in Wisconsin. Respondents were asked if they had received a reminder letter for Pap or mammography screening within the past year. RESULTS: Among women aged >/=18 years, 12.9% (95% confidence interval [95% CI] = 10.1-15. 6) received a Pap test reminder within the past year, while 13.0% (95% CI = 9.3-16.7) of women aged >/=40 years received a mammography reminder. Women without health care coverage were unlikely to receive either type of reminder. Current compliance with screening recommendations was greater among those women who received a reminder letter for Pap tests (94.3 versus 78.1%, P < 0.0001) and for mammography (81.7 versus 59.4%, P < 0.001). In contrast to the infrequent use of cancer screening reminders, 54.2% (95% CI = 50. 1-58.3) and 72.7% (95% CI = 67.6-77.8) of women reported receiving a reminder letter from their dentist or veterinarian, respectively. CONCLUSIONS: Reminder letters for cancer screening services were rarely utilized in this study population. Receipt of a reminder letter was associated with greater compliance with current screening recommendations.     

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.     

Questionnaire color and response rates to mailed surveys. A randomized trial and a meta-analysis

The authors conducted a randomized trial in Geneva, Switzerland, to assess whether response rates to a mailed survey could be increased by printing the questionnaire on green paper. The authors also conducted a meta-analysis of 10 experimental studies that tested the effect of colored questionnaires on response rates. The randomized trial showed no effect (relative risk of responding [RR] = 1.00). The meta-analysis showed that mailing questionnaires on pink paper increased response rates by 12% (RR = 1.12, 95% confidence interval = 1.01 to 1.25, p = 0.04). Other colors had no statistically significant effect (blue: RR = 1.03, p = 0.49; green: RR = 1.02, p = 0.23; yellow: RR = 0.96, p = 0.30). Overall, using colored instead of white paper had no effect (RR = 1.02, p = 0.17). Thus, printing questionnaires on colored paper does not substantially increase response rates in surveys, except for pink paper.     

Association of passive smoking by husbands with prevalence of stroke among Chinese women nonsmokers

Growing evidence suggests that exposure to environmental tobacco smoke may have deleterious cardiovascular effects. Few studies have investigated environmental tobacco smoke exposure in relation to stroke. The authors examined the association between smoking by husbands and stroke prevalence among women nonsmokers in Shanghai, China, where two thirds of men but few women smoke. They analyzed baseline survey data (1997-2000) from a population-based cohort study, the Shanghai Women's Health Study. A total of 60,377 eligible women (aged 40-70 years) were included in the analysis. Information on husbands' smoking status and history of physician-diagnosed stroke was obtained through in-person interviews. Logistic regression was used to compute odds ratios for the associations. There were 526 prevalent cases of stroke reported. The adjusted odds ratios of stroke in women associated with husbands' current smoking of 1-9, 10-19, and > or =20 cigarettes per day were 1.28 (95% confidence interval: 0.92, 1.77), 1.32 (95% confidence interval: 1.01, 1.72), and 1.62 (95% confidence interval: 1.28, 2.05), respectively (p for trend = 0.0002). Prevalence of stroke also increased with increasing duration of husbands' smoking. The authors found that women nonsmokers who lived with husbands who smoked had an elevated prevalence of stroke, and prevalence increased with increasing intensity and duration of husbands' smoking.     

Ultraviolet radiation exposure and risk of non-Hodgkin's lymphoma

Sun exposure has been suggested to increase the risk of non-Hodgkin's lymphoma. The authors analyzed data from a population-based, case-control study of Connecticut women between 1996 and 2000 to study the hypothesis. Women who reported having had a suntan experienced an increased risk of non-Hodgkin's lymphoma with increasing duration (p(trend) = 0.0062) compared with women who reported never having had a suntan. An almost threefold increased risk of non-Hodgkin's lymphoma was observed among women who reported having had a suntan for less than 3 months per year and a suntan history of more than 60 years (odds ratio = 2.8, 95% confidence interval: 1.6, 4.9) compared with those who reported never having had a suntan. For women who reported having spent time in strong sunlight between 9 a.m. and 3 p.m. during the summer, a 70% increased risk of non-Hodgkin's lymphoma was observed for the highest tertile of duration compared with the lowest (odds ratio = 1.7, 95% confidence interval: 1.2, 2.4). The risk increased with increasing duration of time spent in strong sunlight in summer (p(trend) = 0.0051). The risk appears to vary by non-Hodgkin's lymphoma subtypes. Further investigations of the role of ultraviolet radiation on the risk of non-Hodgkin's lymphoma are warranted.     

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.     

An advance letter did not increase the response rates in a telephone survey: a randomized trial

ObjectiveTo test the impact of an advance letter on response and cooperation rates in a nationwide telephone survey, given previous inconsistent results.Study Design and SettingWithin the context of a larger telephone survey, 1,000 Australian households were randomly selected to take part in this trial. Half were randomly allocated to receive an advance letter, whereas the remainder did not receive any advance communication. Response and cooperation rates were compared between the two groups.ResultsA total of 244 interviews were completed, 134 of which were with households that had been sent an advance letter. Intention-to-treat analysis revealed no significant difference in response between those who had received a letter and those who had not (26.8% vs. 22.0%, respectively). In addition, there was no significant difference between the groups in terms of either cooperation (78.4% vs. 79.7%) or response rate (56.3% vs. 57.9%), and no clear differences emerged in terms of the demographic characteristics of the two groups.ConclusionAn advance letter was not seen to be effective in increasing response or cooperation rates in a nationwide telephone survey. Researchers should consider alternative methods of increasing participation in telephone surveys.     

A prospective study of night shift work, sleep duration, and risk of Parkinson's disease

The authors prospectively investigated whether working rotating night shifts was associated with the risk of Parkinson's disease among 84,794 female nurses who reported years of night shift work in 1988 (the US Nurses' Health Study). After 975,912 person-years of follow-up (1988-2000), 181 incident Parkinson's disease cases were documented. Compared with nurses who never worked rotating night shifts, those with 15 years or more of night shift work had a 50% lower risk of Parkinson's disease after adjustment for age and smoking (95% confidence interval: 0.26, 0.97; p(trend) = 0.01). Sleep duration was positively associated with Parkinson's disease risk: The relative risk was 1.84 (95% confidence interval: 0.99, 3.42) when comparing nurses who reported 9 or more hours of sleep per day with those who slept 6 hours or less (p(trend) = 0.005). These data suggest that working night shifts may be protective against Parkinson's disease or that low tolerance for night shift work is an early marker of Parkinson's disease. Conversely, habitual longer sleep duration may be an earlier marker of Parkinson's disease. Because of the novelty and the exploratory nature of these findings, confirmation is needed.     

The association of hypertensive disorders of pregnancy with weight gain over the subsequent 21 years: findings from a prospective cohort study

Obesity is an important risk factor for hypertensive disorders of pregnancy, but most cases of hypertensive disorders of pregnancy occur in women of normal weight. There may be predisposing factors to both hypertensive disorders of pregnancy and obesity. To test this hypothesis, the authors compared changes in body mass index (weight (kg)/height (m)2) over time in women with and without hypertensive disorders of pregnancy. They used data from 3,572 women who received antenatal care at a major public hospital in Brisbane, Australia, between 1981 and 1984 and who were followed up for 21 years. A total of 318 women (8.9%) had experienced hypertensive disorders in the index pregnancy, and 233 of them (73.3%) had a baseline body mass index of or=5 kg/m2 were 59% greater for women who experienced hypertensive disorders of pregnancy compared with those who did not (odds ratio=1.59, 95% confidence interval: 1.24, 2.04). The authors concluded that hypertensive disorders of pregnancy are associated with increased weight gain over 21 years.     

Promoting mammography use through progressive interventions: is it effective?

This study evaluated interventions implemented with women in a health maintenance organization who had not utilized their annual free mammogram referral 45 days (step 2) and 95 days (step 3) after its mailing. The step 2 evaluation compared mammography utilization for women randomly assigned to receive a brief reminder letter or no reminder: 42% of the reminder group vs 28% of the control group obtained mammograms. The step 3 evaluation compared utilization for women randomly assigned to receive a second reminder, a letter suggesting a preventive office visit, or telephone counseling: 29% of those who received telephone counseling, 14% of those who received a letter, and 12% of those who received a second reminder obtained mammograms.     

Will donations to their learned college increase surgeons' participation in surveys? A randomized trial

Effective strategies to maximize response rates to self-administered surveys of clinicians are crucial to minimize response bias. Offers of charitable donations have been assessed for their potential to promote participation of community samples but not in the context of medical specialist samples. We randomized all Australian colorectal surgeons (n = 219) to whom we mailed a survey about clinical practice guidelines to receive either a standard covering letter or one promising a donation to their peak professional organization upon our receipt of their completed survey. Contrary to expectations, surgeons advised that their participation would secure a donation to their college were significantly less likely to return their questionnaire (84.3%, 95% CI 76.0-90.5%) than those receiving a standard letter (93.7%, 95% CI 87.4-97.4%). They also were more tardy in their response (Hazard Ratio = 0.75, 95% CI 0.57-1.00) (P = 0.047). In this context, offering donations to surgeons was counterproductive in enhancing response rates.