May 22, 2002

Vital Decisions: A Pew Internet Health Report

Methodology

This report is based on the findings of a survey of Americans about their use of the Internet.  Most of the results in this report are based on data from telephone interviews conducted by Princeton Survey Research Associates between June 19, 2001, and August 6, 2001, among a sample of 500 Internet users, 18 and older, who have ever gone online to look for health or medical information.  For results based on the total sample, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus 4 percentage points.  In addition to sampling error, question wording and practical difficulties in conducting telephone surveys may introduce some error or bias into the findings of opinion polls.

Interviews for this survey were completed from a pre-screened sample of Internet users who in past surveys had identified themselves as seekers of health information on the Internet.  Once the household was reached, interviewers asked to speak with the individual who had recently completed a telephone survey.  Once the targeted person was on the phone, a few screening questions were asked to make sure that person had in fact gone online to look for health or medical information.

At least 10 attempts were made to complete an interview at every household in the sample.  The calls were staggered over times of day and days of the week to maximize the chances of making contact with a potential respondent.  Interview refusals were re-contacted at least once in order to try again to complete an interview.  The final response rate for the callback portion of this survey is 54%.

This report also contains the results of a national tracking survey conducted by Princeton Survey Research Associates between March 1, 2002, and March 31, 2002, among a sample of 2,410 adults ages 18 and older.  For results based on the total sample, one can say with 95% confidence that the error attributable to sampling and other random effects is plus or minus 2 percentage points.  For results based on Internet users, the margin of error is plus or minus 3 percentage points.

In addition to the survey results, this report contains quotations from two online focus groups conducted by Harris Interactive.  Harris Interactive recruits participants for its qualitative research through the Harris Poll Online and its Qualitative Research Specialty Panel. This panel includes individuals who have expressed an interest in participating in both traditional and online research. When recruited, interested participants complete a screening questionnaire. This information is then used to recruit targeted and low-incidence audiences for both online and offline qualitative research projects.