Background Monitoring medical decisions by the end of existence has become an important issue in many societies. and multivariate logistic regressions, these improvements were assessed in terms of their effects within the response rate, quality of the sample, and variations between Web-based and paper questionnaires. Results The participation rate was 40.0% (n=5217). The respondent sample was very close to the sampling framework. The Web-based questionnaires displayed only 26.8% of the questionnaires, and the Web-based secured procedure led to limitations in data management. The follow-up campaigns had a strong effect on participation, especially for paper questionnaires. With higher participation rates (63.21% and 63.74%), the telephone follow-up and nonresponse studies showed that only a very low proportion of physicians refused to participate because of the topic or the absence of financial incentive. A multivariate analysis showed that physicians who solved on the Internet reported less medication to hasten death, and that they more often required no medical decisions in the end-of-life process. Conclusions Varying contact modes is a useful strategy. Using a mixed-mode design is interesting, but selection and measurement effects must be analyzed further with this sensitive field. (End of Existence in France, abbreviated as EOLF) was carried out in 2010 2010 from the Institut national dtudes dmographiques (INED), with the purpose of describing end-of-life medical decisions in the French context . Compared to earlier studies, EOLF comprised several improvements, including a mixed-mode process (internet and postal questionnaire) as well as postal and telephone follow-ups, combined with postal or email reminders sent from the medical government bodies (private hospitals and regional health agencies). It also comprised a nonrespondent telephone survey to assess nonresponse bias. The aim of this paper was to describe and evaluate the methodological improvements of EOLF and to assess their impact on data collection quality. It explains response rates, representativeness of the sample, motives for nonresponse, and differences resulting from the data collection modes. Regarding the mixed-mode strategy, we assessed whether the choice of Internet over paper questionnaires was linked to the characteristics EPLG1 of the participating physician or of the deceased person, and whether this choice experienced an impact within the reporting of end-of-life medical decisions. Methods Retrospective Design We chose to sample deaths and not physicians [4-8] for the same reasons given by Chambaere et al . A representative sample of 14,999 deaths was selected from the CepiDc (and (CCTIRS) in January 2010 and authorized by CNIL (authorization quantity 1410166). Statistical Analysis Samples were explained using percentages and bivariate analyses with Pearson chi-square checks. Three multivariate logistic models (providing adjusted odds ratios and 95% confidence intervals) were also computed when comparing Web-based and paper questionnaires. These models tested whether the choice of Web-based questionnaires was linked to physician characteristics (Model 1), death characteristics (Model 2), or both units of characteristics (Model 3). All statistics were computed using SAS V9.3 and were nonweighted unless specified. Results Preliminary Recognition of Death Certificates, Physicians, and Participation Rate Overall, 14,080 death certificates (93.87% of the initial sample of deaths) with recognized physicians were available for the survey, corresponding to 11,828 different physicians (Table 1). The final sample was reduced to 13,460 deaths because of postal address problems (changes in professional location, etc). From this sample, 5217 questionnaires were completed and returned. This led to a participation rate of 40.02% . We used ML204 manufacture the standard Response Rate 2 from your American Association for General ML204 manufacture public Opinion Study (AAPOR). The method used was 5217 questionnaires/(5217 questionnaires + 1506 refusals + 449 characters not ML204 manufacture delivered + 561 physicians who could not respond because the survey did not concern them [sudden death, not the physician in charge of the patient, could not remember the case or could not find the file] + 49 additional reasons for nonresponse [eg, death of respondent, retirement, not available ML204 manufacture during data collection] + E[6287 neither responding nor refusing]) = 40.02%. E is the estimation of the proportion of eligible instances (in this case, 92.10%). E was determined by the percentage of the sum of questionnaires + refusals + others, to the sum of questionnaires + refusals + others + non-eligible individuals. We counted as non-eligible those who mentioned in the follow-up survey which they did not respond because the survey did not concern them (not in charge of the patient, not a forensic scientist, could not remember or find the file of the person, etc). An additional analysis of the follow-up file (not mentioned in the table) showed the response rate varied with the individuals characteristics. It assorted by age of the deceased (from 42.12% for deceased individuals aged 18-39 to 35.03% for those aged 90+), place of death (from 29.15% for nursing homes to 17.17% for general public locations and 40.20% for general public private hospitals), and region of residence (from 30.76% in the Mediterranean region to 40.42% in.