Initial nonresponders had an increased response rate after repeated questionnaire mailings. Absolutely relative: how research results are summarized can affect treatment decisions.
There is a growing evidence base on methods to improve response rates in surveys among patients. This study aimed to determine the additional effect of two intensive follow-up procedures compared to a simple follow-up procedure.
                Randomized controlled trial that compared repeated mailing of the questionnaire and a request to explain nonparticipation with a simple reminder card. The study population comprised 955 elderly adults registered with 26 general practitioners in The Netherlands.
                A total of 530 adults (56%) returned the questionnaire within 3 weeks and a total of 640 (67%) after follow-up. Repeated mailing of the questionnaire had additional effect compared to the simple reminder card in the group of initial nonresponders (relative risk=1.60, 95% confidence interval: 1.11-2.31), but not regarding the overall response rate. A request to explain nonparticipation did not have additional effect.
                Repeated mailing of the questionnaire increased the effectiveness of follow-up among initial nonresponders. To determine whether alternative methods of presenting a contrast between the same two quantities in descriptions of research results could lead to different treatment decisions by physicians.
                We conducted a survey of practicing physicians and of faculty and fellows in training programs in clinical epidemiology and social science research methods. Each questionnaire presented results from a published study of either hypertension or hypercholesterolemia in two different ways: once as the relative change in the outcome rate and once as the absolute change in the outcome rate. We asked respondents to read each summary and indicate how the information contained in the summary would influence decisions about treatment.
                Of the 235 physicians who completed the questionnaire, 108 (46%) gave different responses to the same results presented in different ways. Of these, 97 (89.8%) indicated a stronger inclination to treat patients after reading of the relative change in the outcome rate (p less than 0.0001).
                The manner of presentation of results can influence physicians' judgments about the treatment of patients.
The small number of participants and the short follow-up period impede definitive conclusions on comparative effects.