The BWHS, a prospective follow-up study of 59,000 African-American women, began in March 1995. Black women aged 21–69 years from all regions of the United States were enrolled in the study through postal questionnaires sent to subscribers to Essence
magazine, members of black professional organizations, and friends of respondents (19
). Enrollment was completed in 1995. Twice a year, participants have received a newsletter updating them on the status of the research and informing them of current and future questionnaire mailings. Follow-up questionnaires have been mailed every 2 years (20
). Eight mailings of paper questionnaires were made throughout each 2-year period. The first paper mailing of each cycle was carried out using nonprofit postage; the fourth and seventh mailings were done by priority mail; and the other 5 questionnaires were mailed first class. Since 1999, participants have been asked to provide us with their e-mail address. During the 2003, 2005, and 2007 questionnaire cycles, all participants in the BWHS were given the option of completing either the paper version of the questionnaire or the Web version. Data collected from these 3 follow-up cycles were used for the present analyses.
The BWHS questionnaires contained a wide range of questions assessing current health status and exposures. The participants were asked to report on their medical conditions, current medication usage, weight, menstrual/reproductive history, physical activity, cigarette smoking, and alcohol use. Dietary intake was ascertained with a modification of the short Block-National Cancer Institute food frequency questionnaire (21
). Additional questions about education, occupation, health care, religion, insurance, waist/hip measurement, violence, night work, and other factors were added to particular questionnaires. The women's addresses have been linked to 2000 US Census data at the block group level. A neighborhood socioeconomic status score was derived through factor analysis based on 6 variables representing wealth and level of education (e.g., median housing value), with a higher score indicating higher socioeconomic status (22
). Prudent and Western dietary patterns based on the food frequency responses were identified through factor analysis (23
Both the Web and paper versions of the questionnaire were designed in-house, allowing us to accurately assess the amount of time needed for development of the questionnaires. The first Web questionnaire required 120 hours of a computer programmer's time to design, test, and implement. The time required has subsequently decreased, with design, testing, and implementation taking 100 hours in 2007. The paper questionnaire was designed in-house using TeleForm software (Autonomy Cardiff, Inc., Vista, California). Approximately 40 hours of a programmer's time were required to design and test each new paper questionnaire.
Each Web questionnaire was designed with the same questions and layout as the corresponding paper questionnaire. All primary questions were permanently visible on the Web questionnaire (i.e., they could not be skipped). Both the paper questionnaire and the Web questionnaire directed participants to skip subquestions if they did not apply, with a visible line pointing to the next question and indented subquestions on the paper questionnaire and shaded or invisible subquestions on the Web questionnaire. The Web questionnaire reminded participants if they had skipped a primary question but did not require them to complete this skipped question in order to move on to a subsequent page of the questionnaire.
At the beginning of each of the 3 follow-up cycles under study, participants who had provided us with at least 1 e-mail address and who were known to be alive and had not refused further participation were sent an e-mail message with a link to the latest BWHS Web questionnaire. A reminder e-mail was sent 3 weeks later to all participants who had not yet completed the Web questionnaire. All those who did not respond to the Web questionnaire within the first 6 weeks were mailed a paper questionnaire. In the cover letter of the paper questionnaire, there was a reference to the Web questionnaire, informing participants of the option to complete either questionnaire. This allowed women who did not previously provide us with an e-mail address an opportunity to complete a Web questionnaire. Every 2–3 months, for 2 years, a follow-up mailing was sent to all nonresponders, again listing the Web questionnaire as an option. A reminder e-mail was also sent out to all nonresponders 5–6 times during the follow-up cycle. Additional reminders to complete questionnaires either by mail or by Web were included in the BWHS biannual newsletters. At the end of a 2-year follow-up cycle, persons who did not respond to the paper or Web questionnaire were considered nonrespondents.
Once the paper questionnaires had been returned, staff carried out the following quality control steps: 1) Record receipt of the survey; 2) separate data pages from contact information pages; 3) review all pages for stray marks or text outside of data fields that would not be caught by the scanner; 4) scan the surveys; 5) verify the accuracy of the scanned data; 6) update addresses; 7) code open text responses; 8) review all dates of birth to confirm that the right individual had completed the survey; and 9) review all outliers for particular questions. Web surveys did not require the first 5 quality control steps. Because the participant's month and year of birth were required to access the Web questionnaire, review of birth dates was minimal for the Web questionnaire. In addition, minimal work was required to check outliers on the Web questionnaire, because it included prompts to have participants review their response if a response they had entered would be considered out of range. To calculate the time needed to process each returned questionnaire, 3 staff members each completed the above tasks on 100 records for each of the 3 follow-up cycles. Their time per task/cycle was then averaged to estimate staff processing time for each paper and Web questionnaire received.