***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: A health-related mailed survey was conducted to investigate the effect of follow-up mailings to response rates . In addition , the answer distributions among early and late respondents were compared to check non-response bias . Approximately 3,000 persons aged 40 - 64 were r and omized into two groups ; a question naire with four pages ( twenty-two questions ) was assigned to the first group , and a question naire with eight pages ( thirty-five questions ) to the second group . Both question naires contained questions of current health status , health-related practice , smoking status , etc . Follow-up mailings were sent twice to non-respondents . Response rates were increased from 38 % to 62 % by the first follow-up mail , and to 71 % by the second follow-up mail . Although the length of the question naire did not affect response rates , response rates among the older subjects was higher than the younger subjects . Positive response to current smoking status was 10 % lower among early respondents than late respondents , collected after the second follow-up mailing , and response to regular participation in physical/medical checkup was 15 % higher among early respondents , whereas there were few differences for answers to other questions . Odds ratios between current health status and several health-related questions may not be biased by late response . However , increased response rates are needed to prevent non-response bias , because there were some differences in responses from follow-up mailings STUDY OBJECTIVE --The aim of the study was to determine whether complete anonymity improves the response rates to a postal question naire . DESIGN --The study derived from a series of postal surveys on AIDS knowledge conducted on six different date s in 1986 and 1987 . The sample was r and omly divided into two , each group being sent the same question naire . One group was informed that the replies were anonymous , the other that they were not . The latter were sent reminders . SETTING --Recipients of the question naires were drawn from the Southampton electoral rolls . PARTICIPANTS --300 people in each survey ( total 1800 ) were sent question naires , representing on each occasion a different 1:500 systematic sample . RESULTS --Response rate was 49 % for the anonymous question naires and 51 % for the numbered question naires . Reminders boosted the response in the numbered group to 72 % . CONCLUSIONS --There is no evidence that anonymity improves response to postal question naires , but the use of reminders may do so Mailing surveys to low-income population s is often avoided because of concern about low response rates . In this study , the authors used a mailed survey of a low-income population to test whether $ 1.00 or $ 2.00 cash-response incentives were worth the expense and whether 2-day priority mail ( $ 2.90 postage ) would yield a sufficiently higher response rate than certified mail ( $ 1.52 postage ) to justify its cost . In 1994 , 2,243 r and omly selected families in subsidized health care programs in Pierce County , Washington , were r and omly sent no incentive , $ 1.00 , or $ 2.00 in the first of three mailings . For the third mailing , nonrespondents were r and omly assigned to receive either certified or 2-day priority mail . After 4 weeks , the response rates were 36.7 % , 48.1 % , and 50.3 % for the no-incentive , $ 1.00 , and $ 2.00 groups , respectively . After three mailings , the cost per response was the lowest for the group that received $ 1.00 . The response rate for the certified mailing ( 28.1 % ) was significantly higher than the rate for the more expensive priority mailing ( 21.7 % ) . No incentive-related bias was detected . The authors concluded that the most efficient protocol for this low-income population was to use a $ 1.00 incentive in the first mailing and a certified third mailing OBJECTIVES The effects of incentive size on physicians '  response rates to a mail survey were determined . METHODS One thous and US primary care physicians were assigned r and omly to receive a survey with either a $ 5 bill or a $ 2 bill as an incentive . For each of the two incentive groups , the overall response rate for three mailing waves , the total cost , and the total cost per usable response were measured . RESULTS The response rate among those receiving the $ 5 bill ( 61 % ) was 32 % higher than the response rate among those receiving the $ 2 bill ( 46 % ) ; overall costs were slightly higher in the $ 5 group , but the cost per response for each group was similar ( $ 15.46 versus $ 14.93 ) . For the same cost , a higher response rate could have been achieved in the $ 2 group if costs saved from foregoing the third mailing were instead used to increase the incentive for a portion of the subjects . CONCLUSIONS A $ 5 bill incentive yielded a higher response rate among the physicians in this study than did a $ 2 bill incentive . Moreover , the powerful effect of the incentive size , combined with the consequent decline in the costs of subsequent mailing waves , suggests that re sources in a fixed survey budget are allocated more efficiently to increasing the initial incentive rather than to providing a third wave to nonresponders BACKGROUND Patient surveys are becoming increasingly common and already are an obligatory activity to qualify for a Better Practice Program Grant . Strategies to increase return rates remain unevaluated in Australian general practice . AIM To evaluate the effectiveness of an instant lottery ticket as a response-aiding technique in patient surveys . METHOD A r and om sample of adult patients was selected from an age-sex-disease register , stratified by sex and r and omised to receive an instant lottery ticket with the self-administered question naire mailed out in December 1994 . RESULTS There was no significant difference by group either for women ( P = 0.68 ) , men ( P = 0.88 ) or both sexes combined ( P = 0.68 ) . However , irrespective of inclusion of the lottery ticket , men were significantly less likely to return question naires than women ( P = 0.02 ) . CONCLUSIONS Instant lottery tickets do not increase return rates to question naires and are not recommended . Other strategies need to be tested , particularly to involve male patients in general practice research Although self-administered question naires are major sources of information in epidemiology , comparatively little has been done to study practical aspects of design and mailing . The objective of this study was to evaluate various measures taken to increase the response rate . A question naire was mailed in July 1995 to a r and om sample ( n = 2,000 ) of the Swedish population aged 20 - 79 years . Using a r and omized factorial study design , the question naire and mailing procedures were changed in three ways : preliminary notification , length of the question naire , and mention of telephone contact . The overall question naire retrieval rate was 49 % . Preliminary notification ( adjusted odds ratio of receiving a completed question naire = 1.30 , 95 % confidence interval ( CI ) 1.08 - 1.56 relative to the absence of preliminary notification ) and short length of the question naire ( odds ratio = 1.24 , 95 % CI 1.04 - 1.48 relative to a long question naire ) were both independently associated with a higher retrieval rate . Of eight possible combinations , the one comprising preliminary notification , a short question naire , and no mention of telephone contact gave the highest retrieval rate , 56 % . The lowest retrieval rate , 40 % , was observed for the combination of no preliminary notification , a long question naire , and mention of telephone contact . Young age , male sex , and urban residence significantly lowered the retrieval rate . Although there was a positive association between the question naire retrieval rate and partial nonresponse ( missing answers in retrieved question naires ) , the marginal losses due to the latter did not cancel the gains by optimized mailing routines . Old age was the strongest determinant of partial nonresponse . The data provide evidence that design and mailing strategies , as well as demographic characteristics , may greatly influence the response rate of mailed epidemiologic question naires BACKGROUND A range of factors have been shown to affect the response rate to mailed question naires , but particular strategies to improve patients ' response in trials conducted in general practice require further study . METHODS Non-responders in a larger trial were r and omized to receive a telephone or recorded delivery reminder on the third contact . The cost of administration of each method was estimated . RESULTS Significantly more patients returned completed question naires when sent question naires by recorded delivery , although the cost per patient contacted was nearly three times more than for contact by telephone . CONCLUSION Our study indicates that sending reminders by recorded delivery , although more expensive , is more effective than telephone reminders for recruiting patients to a study in general practice using research question naires In two experiments , findings with college undergraduates ( Ns = 154 and 137 ) suggest social desirability may not affect responses to survey items on HIV-related behaviors and results may not be constrained by anonymity Objective : To assess whether length of question naire affects response rates . Methods : A quasi-r and omised trial of women aged 70 years and over in a general practice in Engl and .  Three question naires of different lengths : a clinical question naire ( four pages ) ; the same question naire plus the EuroQol ( five pages ) ; the same question naire plus the SF-12 ( seven pages ) . The impact of length on the proportion of returned question naires and item completion rates was assessed . Results : In total , 847 question naires were mailed ;  response rates were 49 % , 49 % and 40 % to the short , medium and long question naires , respectively . This difference was statistically significant when the short question naire 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 question naire did not differ . Respondents did not differ in age or self-reported health status between the three groups . Conclusions : Increasing the length of a question naire from five to seven pages reduces response rates from women aged 70 years and over . However , lengthening a question naire does not seem to affect the quality of responses to questions near the front of the question naire The purpose of this study was to investigate how response rates to a postal question naire are affected by title and length of the survey instrument . Five question naires , which differed according to title and length , were design ed . Each question naire was mailed to a r and om sample of one thous and Norwegian women aged , 35—49 years . A total of 3,106 question naires were returned ( 62.1 % ) . The highest response rate ( 70.2 % ) was achieved by a two-page question naire entitled ` ` Women and Cancer ' ' . An otherwise identical question naire entitled ` ` Oral Contraceptives and Cancer ' ' had a response rate of 60.7 % . Question naires entitled ` ` Women and Cancer ' ' with a length of four and six pages had a response rate of 62.8 % and 63.3 % , respectively . The four page question naire entitled ` ` Women , Lifestyle and Health ' ' had the lowest response rate of 57.1 % . This study shows that in a general population of Norwegian women the title of a postal question naire influences the response rate . The results indicate that although the shortest question naire had the highest response rate , the most extensive survey instrument did not have the lowest response rate . The distribution of risk factors for breast cancer did not vary according to response rate or design of question naire . The overall findings of this study suggest that the benefits from the increased information obtained from extensive postal question naires out-weighs a potential non-response bias due to a somewhat lower response rate In 1989 , the authors tested the effectiveness of two response-enhancing techniques , a postage stamped or franked return envelope and a prenotification letter , in a survey of pregnancy among 10,047 resident physicians in the United States . The techniques were r and omly assigned using a factorial design . No significant interactions were observed between the techniques . After two mailings , those who received a stamped return envelope had a response of 71.2 % , compared with 68.2 % for those who received a franked return envelope ( 95 % confidence interval 1.3 - 4.9 % ) . Men who received the stamped envelope had a 5.9 % greater response than those who received the franked envelope ( p less than 0.001 ) , but the type of postage did not influence response among women ( p = 0.84 ) ; this interaction was statistically significant ( p = 0.006 ) . Physicians who received a prenotification letter had a response of 69.0 % , compared with 70.5 % for those who did not receive the letter ( 95 % confidence interval -3.3 to 0.2 % ) . The authors conclude that seemingly minor changes in survey design could have saved from 12 % to 19 % of the total cost of the study To evaluate response‐aiding strategies feasible in large surveys , we r and omly allocated general practitioners ( GPs ) to one of four intervention groups : Group 1 received ‘ exhaustive ’ telephone prompts by a medical peer in advance of a question naire ; Group 2 , inclusion of an embossed pen with the question naire ; Group 3 , an advance letter prompt ; and Group 4 , a ‘ single attempt ’ advance telephone prompt by a non‐medical research assistant . Follow‐up procedures were identical . Response rates by group were not significantly different overall ( χ24.59 , df=3 , p=0.20 ) although advance prompts by a medical peer were significantly more effective than other strategies for male GPs . The difference in overall response rates between males ( 63 % ) and females ( 74 % ) was significant ( χ2=15.40 , df=1 , p<0.01 ) . No other response bias was evident . Our demonstration of a significant interaction between respondent sex and response‐aiding strategy invites further research BACKGROUND Low response rates are acknowledged as a potential source of bias in survey results . Response rates are a particular problem in surveys of GPs . Thus , the methods used to encourage response to mailed surve 
    Output:
    
Health research ers using postal question naires can improve the quality of their research by using the strategies shown to be effective in this systematic review