Methodologic challenges of e-health research.

In this article, research-based strategies used in a web-based study to assess the impact of participation in cancer-related mailing lists on cancer survivors and caregivers are highlighted. The paper presents alternative methods of measuring response rates in Internet surveys. Response rate estimation, based on American Association for Public Opinion Research guidelines, ranged between 15% and 24.9% for the study. Several strategies were implemented to increase survey participation and reduce item nonresponse. Few participants opted for a telephone survey as an alternative to a web-administered design (mixed-mode administration). Using time-stamp data to diagnose places in the questionnaire where respondents prematurely exited or broke off survey participation, we were able to decrease premature break offs. A lottery was also implemented to increase response rates. The experience of obtaining institutional review board approval for the lottery is also described. Preliminary data indicate slight increases in response rates subsequent to implementing the lottery.