Cognitive interviewing is a method for systematically pretesting questionnaires to understand how respondents interpret questions and to identify problems they have providing answers. This method can uncover difficulties with questions and guide revisions before fielding a survey. NIOSH scientists developed a questionnaire to study asthma among healthcare workers and submitted it to social scientists at the National Center for Health Statistics (NCHS) for cognitive interviewing. The questionnaire included 39 questions in four categories: medical history, work history, home exposures, and occupational exposures. NCHS enlisted 21 healthcare workers to complete the paper version of the survey instrument and five healthcare workers to complete the online survey instrument. Upon completing the survey, participants were interviewed to probe their responses to questions. Testing of the survey emphasized question content and understanding with the paper version and usability and visual impact with the online version. For the paper survey instrument, participants correctly answered questions related to their medical and work histories. For example, participants were able to properly identify their relevant job category, even though various job titles are used for the same healthcare job. Most response errors concerned questions about occupational exposures, including difficulty distinguishing between general cleaning and high-level disinfecting, an inability to recall chemicals or product brands used during the workday, and inaccurate estimates of the number of hours per day they performed specific tasks. For the online survey, participants reported difficulty completing tables asking for information on chemical/products used and tasks completed during the workday. Specifically, the tables were too complex for easy comprehension when displayed on the computer screen. In addition, participants complained they had to click through too many screens to complete the survey. The questionnaire was revised to incorporate lessons learned from the cognitive interviews. Actions to reduce response errors included rewording or reorganizing questions, listing examples of chemicals and product brands to help participants recall which ones they used, and eliminating the need for participants to calculate the number of hours per day they performed tasks. For the online survey, complex chemical/product and task tables formerly presented in a single screen display were broken up and distributed across several screens to simplify presentation. Questions outside tables were grouped so that more appeared per screen, leading to an overall reduction in the number of screen displays and mouse clicks. Cognitive interviewing provided substantive guidance that will reduce time to complete the survey and minimize response error.
M. J. Humann, National Institute for Occupational Safety and Health, Morgantown, WV