***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE Primary care physicians are increasingly being asked to participate in postal surveys . Difficulties in achieving adequate response rates among physicians have been reported . We investigated the effect of two low-cost interventions on response to a  primary care physician postal question naire . STUDY DESIGN AND SETTING A 2x2 factorial trial was developed within the context of a national survey assessing views and practice s of physicians regarding prostate-specific antigen testing . We evaluated question naire order ( version 1 : demographics first , version 2 : topic-specific questions first ) and written precontact . A national data base of primary care physicians was compiled . One thous and five hundred ninety-nine physicians were r and omly selected , stratified by health board , and r and omized . RESULTS 47.9 % of eligible physicians completed a question naire . There was a statistically significant 5.1 % higher response rate among physicians receiving version 1 of the question naire than those receiving version 2 ( 50.6 % vs. 45.4 % , P=0.05 ) ; the adjusted odds of response were significantly raised ( odds ratio=1.24 ; 95 % confidence interval=1.01 - 1.54 ) . Precontact result ed in a nonsignificant 3.6 % increase in response ( 49.8 % vs. 46.2 % ; P=0.16 ) . The interventions did not interact . CONCLUSION Ordering question naires with general questions first can significantly increase response rates , whereas precontact can achieve a modest increase . These strategies may enhance response while adding little to the cost of a physician survey Objective : Recruitment of African Americans into health research studies is a major challenge . This report describes a study of different methods and strategies to recruit African Americans into a population -based assessment of cancer behavioral risk factors . Methods : African Americans ages 18 to 70 years in North Carolina ( n = 5,000 ) were r and omly selected from the Department of Motor Vehicle rosters and assigned at r and om to one of five different recruitment strategies based on variations of approach letters ( generic versus culturally sensitive ) and inclusion , exclusion , or promise of a small incentive . Prospect i ve participants were sent an 11-page question naire by mail but could complete it by telephone or Internet as well as by mail . Results : The overall response rate was 17.5 % ( 747 completed surveys of 4,276 delivered ) : 655 , 84 , and 8 by mail , Internet , and telephone , respectively . Among eligible respondents , response was significantly higher for incentive-based than nonincentive strategies ; 23.9 % for the generic letter plus incentive compared with 15.8 % for the generic letter only ( P < 0.001 ) . The culturally sensitive letter had little effect on participation ( 15.8 % for both the generic and culturally sensitive letters ) . The  mean age of eligible respondents was 43.9 years , 41 % were male , 37 % were college graduates , and 75 % were overweight/obese . There were no differences in respondent characteristics by assigned recruitment strategy . Conclusions : Incentive-based strategies yielded the highest survey responses , whereas a culturally sensitive letter did not appreciably increase participation among African Americans in North Carolina . This study adds to what is known about culturally sensitive recruitment strategies for African Americans and challenges their usefulness in survey-based studies 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 The objective of this study was to compare the impact of closed- versus open-ended question formats on the completeness and accuracy of demographic data collected in a mailed survey question naire . We surveyed general internists in five Canadian provinces to determine their career satisfaction . We r and omized respondents to receive versions of the question naire in which 16 demographic questions were presented in a closed-ended or open-ended format . Two questions required respondents to make a relatively simple computation ( ensuring that three or four categories of response added to 100 % ) . The  response rate was 1007/1192 physicians ( 80.0 % ) . The proportion of respondents with no missing data for all 16 questions was 44.7 % for open-ended and 67.0 % for closed-ended formats ( P < 0.001 ) . The odds of having missing items remained higher for open-ended response options after adjusting for a number of respondent characteristics ( 2.67 , 95 % confidence interval 2.01 to 3.55 ) . For the two questions requiring computations focused on professional activity and income , there were more missing data ( P = 0.02 , 0.02 , respectively ) but fewer inaccurate responses ( P = 0.009 , 0.20 , respectively ) for the open-ended compared to the closed-ended format . Investigators can achieve higher response rates for demographic items using closed format response options , but at the risk of increasing inaccuracy in response to questions requiring computation 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 Postal health surveys in the general population can provide important information to assist with planning and service provision . 1 High response rates are needed to ensure validity and to minimize costs from following-up non-responders . 2 Only a small number of studies have examined methods to increase response rates in postal surveys . Using a post-office stamp rather than a prepaid business reply envelope may seem more personal and encourage participants to return the question naire . However , results from trials evaluating this are inconsistent and limited to health professionals in North America . 3–5 Consequently there is little evidence to inform the choice of reply envelopes in postal surveys of the general UK population . This was determined in the current study . Methods The sample consisted of 633 adults r and omly selected from a health authority register in the north west of Engl and . A computer-generated r and omization list , stratifying on sex and age ( 18–45 , 46–64 , у65 years ) was used to allocate participants to receive one of two types of reply envelopes , both printed with the return address . One group ( POS ) received a reply envelope with a first-class post-office stamp , while the second group ( PPB ) received a prepaid business-franked envelope to return their health question naire . The initial mail-out included the 16-page health question naire , a personalized letter from the Director of Public Health and one of the two return envelopes . Question naires were sent out in March 2001 and non-responders were sent a reminder postcard 10 days later . The primary outcome was the difference in response rates between the two types of reply envelopes , after follow-up reminders had been sent measured at 4 weeks after posting the survey . The χ 2 test was used to examine statistical significance . Approval was obtained for the study from the Local Research Ethics Committee.2 % ) question naires were returned within 10 days , from the two allocation groups , respectively . After sending reminders to the 182 non-responders in the POS group and 195 in the PPB group ( excluding 6 and 4 participants respectively later found to be not living at that address ) , the return rate increased to 182 ( 58.7 % ) and 179 ( 57.2 % ) in the two groups . This difference of 1.5 % between the two groups is unlikely to be important and was not statistically significant ( χ 2 = 0.08 , P = 0.77 ) . No important difference was observed in return rates between the POS and the PPB group for men or women and across three age groups . However , return rates 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 We studied women 45 - 54 years of age from two communities who failed to return a mailed survey in an experiment to assess the impact on interviewing response rates of leaving messages on telephone answering machines at the time of telephone follow-up . There were 88 and 103 subjects assigned to the " message " and " no message " groups , respectively . After adjustment for age , interviewer , and community , leaving messages increased the rate of reaching a household by about 15 % and improved the overall interviewing response rate by about 15 % as well . This improvement was more apparent in women from the higher socioeconomic status community Study objective : To assess the effectiveness of a telephone reminder in increasing responses to postal surveys and to calculate the differential costs per completed question naire . Design : R and omised controlled trial . Setting : Australian university and rehabilitation medicine practice . Participants : The trial was conducted in 1999 among the 143 non-respondents to a question naire about work related neck and upper body disorders . The question naire was sent to two Australian female sample s : 200 office workers ( Sample A ) and 92 former rehabilitation medicine patients ( Sample B ) . A reminder letter , another copy of the question naire and a final letter were sent at two week intervals . Half of the non-respondents within each sample were r and omly selected to receive a telephone reminder just after the second mailout of the question naire . 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 
    Output:
    
Health research ers using postal and electronic question naires can increase response using the strategies shown to be effective in this systematic review