***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: 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 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 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 surveys and the influence of inducements in maximizing response rates are fundamental issues to be examined when addressing the problem of response bias . AIM To increase the overall response rate to a national study of GPs and to explore the effects of financial and non-financial inducements on response rates . METHODS Two mailing waves of a postal question naire to a 20 % r and om sample of all GPs in Engl and and Wales had achieved a 33 % response rate . For the third mailing wave , the non-responding GPs were then divided into a control group , a group who were offered a donation to charity to complete the question naire and a group who were offered cash . The charity and cash groups were further subdivided into 5 pounds and 10 pounds groups to assess the effect of the size of the inducement offered . For the control group , a fourth wave was sent the offer of a 5 pounds or 10 pounds incentive . RESULTS Response was positively affected by the offer of an inducement . Cash , however , had a more substantial effect than the offer of a donation to charity .  Older GPs were less likely to participate overall , whereas male GPs were more likely to respond to a cash inducement . Doctors who had seen more patients were less likely to reply earlier and were more likely to respond to the offer of cash . CONCLUSIONS Primary care is going through many changes , some of which have increased the workload of the GP . It may now be that , to achieve the response rates needed to vali date policy-related research , the offer of inducements will become a necessary part of the research process CONTEXT Health plan utilization review rules are intended to enforce insurance contracts and can alter and constrain the services that physicians provide to their patients . Physicians can manipulate these rules , but how often they do so is unknown . OBJECTIVE To determine the frequency with which physicians manipulate reimbursement rules to obtain coverage for services they perceive as necessary , and the physician attitudes and personal and practice characteristics associated with these manipulations . DESIGN , SETTING , AND PARTICIPANTS A r and om national sample of 1124 practicing physicians was surveyed by mail in 1998 ; the response rate was 64 % ( n = 720 ) . MAIN OUTCOME MEASURE Use of 3 different tactics " sometimes " or more often in the last year : ( 1 ) exaggerating the severity of patients ' conditions ; ( 2 ) changing patients ' billing diagnoses ; and /or ( 3 ) reporting signs or symptoms that patients did not have to help the patients secure coverage for needed care . RESULTS Thirty-nine percent of physicians reported using at least 1 tactic " sometimes " or more often in the last year . In multivariate models comparing these physicians with physicians who " never " or " rarely " used any of these tactics , physicians using these tactics were more likely to ( 1 ) believe that " gaming the system " is necessary to provide high- quality care today ( odds ratio [ OR ] , 3.67 ; 95 % confidence interval [ CI ] , 2.54 - 5.29 ) ; ( 2 ) have received requests from patients to deceive insurers ( OR , 2.44 ; 95 % CI , 1.72 - 3.45 ) ; ( 3 ) feel pressed for time during patient visits ( OR , 1.69 ; 95 % CI , 1.21 - 2.37 ) ; and ( 4 ) have more than 25 % of their patients covered by Medicaid ( OR , 1.60 ; 95 % CI , 1.08 - 2.38 ) . Notably , greater worry about prosecution for fraud did not affect physicians ' use of these tactics ( P = .34 ) . Of those reporting using these tactics , 54 % reported doing so more often now than 5 years ago . CONCLUSIONS A sizable minority of physicians report manipulating reimbursement rules so patients can receive care that physicians perceive is necessary . Unless novel strategies are developed to address this , greater utilization restrictions in the health care system are likely to increase physicians ' use of such manipulative " covert advocacy " tactics Objective : This study measures the effect of an intervention to improve mailed survey response rates Euthanasia and physician-assisted suicide are highly controversial societal issues ( 1 - 3 ) . In the past decade , there have been numerous surveys of physicians throughout the world on euthanasia and  physician-assisted suicide  ( 1 , 4- 14 ) . Nevertheless , important deficiencies in information remain . First , most studies have been snapshotssurveys of attitudes or experiences at one point in time ( 15 ) . Second , more than a fourfold variation exists in the reported rate of requests for and performance of euthanasia and physician-assisted suicide among U.S. physicians , making it difficult to draw definitive conclusions about physician practice s ( 10 , 11 , 13 , 14 ) . Most important , almost all surveys of physicians have focused exclusively on euthanasia or physician-assisted suicide as isolated practice s. None of the existing data provide insight into how these practice s relate to optimal end-of-life care . To address some of these deficiencies , the American Society of Clinical Oncology ( ASCO ) surveyed all of its U.S. members about end-of-life care practice s ; we report part of the results of that survey . Our focus on oncologists is appropriate because data from the Netherl and s and Oregon indicate that more than 70 % of patients using euthanasia or physician-assisted suicide  have cancer ( 7 , 16 ) . In the United States , where patients with cancer tend to be treated by specialists , oncologists are likely to have to address the issue of  euthanasia  and  physician-assisted suicide  more often than other physicians ( 11 , 14 ) . Methods Physician Identification General eligibility requirements for the study were membership in ASCO in 1997 , which included at least 85 % of all oncologists in the United States , and being active in the management of patients at the very end of life . Two groups were identified for participation ; neither was compensated . First , all 8715 oncologists from the United States who were ASCO members were mailed a survey  with a postage-paid return envelope . Physicians who did not return the survey after 4 weeks were mailed a reminder letter with another copy of the survey . Of U.S. oncologists , 6642 were eligible ; 2645 of these physicians completed the survey ( response rate , 39.8 % ) . Second , 1550 medical , surgical , radiation , and pediatric oncologists were r and omly selected in a prospect i ve manner to be contacted through personal telephone calls and additional mailings urging them to complete the survey . Of these physicians , 1273 were eligible and 655 completed the survey ( response rate , 51.5 % ) . The responses to all questions about euthanasia and physician-assisted suicide from these cohorts were statistically indistinguishable ; therefore , responses from the two groups were combined , providing a total of 3299 responses . Survey Development In conjunction with the Center for Survey Research , a multidisciplinary task force created a survey instrument . After pretesting among oncologists , the instrument was finalized with 118 questions in eight areas . The precise wording of the questions that we analyzed is provided in the Appendix Table . Because the terms euthanasia and physician-assisted suicide can be both misunderstood and emotionally charged , previously reported descriptions of these activities were used in all questions ( 1 , 13 , 15 ) . Statistical Analysis Comparisons among groups were performed by using the Pearson chi-square test of independence . Predictors of support for and performance of physician-assisted suicide and euthanasia were identified by using stepwise logistic regression analysis . To minimize type I errors and reduce the probability of identifying factors associated with differences that are not clinical ly meaningful , the selection criteria for entry into the model were set at an level of 0.005 . Potential explanatory variables in all analyses were age , sex , religious affiliation , religiosity , importance of religious beliefs , death of a relative within the past 5 years , specialty , rural or urban practice , academic practice , amount of time in patient care , number of new patients in the past 6 months , and number of patients who died in the past year . Additional explanatory variables were barriers to providing optimal care to terminally ill patients , time available to talk to terminally ill patients , perceptions of reimbursement levels , perceived difficulties in getting patients the care that they required , poor pain management decisions , proportion of terminally ill patients who are depressed , and personal responsibility for care of terminally ill patients . Results Table 1 provides basic sociodemographic data on the 3299 U.S. oncologists who participated . Among all ASCO oncologists , 17.3 % are female and 33.4 % work in academic setting s ; these overall values are similar to those among survey respondents . More than 85 % of respondents spent at least half their working time in direct patient care ; 52 % indicated that they devoted more than 90 % of their time to clin 
    Output:
    
RESULTS The effectiveness of prepaid financial incentives , special contacts , and personalization to enhance response rates in surveys of physicians have been confirmed by the existing research .
There is suggestive evidence supporting the use of first class stamps on return envelopes and multiple contacts .