It's About Time: Examining the Effect of Interviewer-Quoted Survey Completion Time Estimates on Survey Efficiency

Declining response rates may introduce bias into survey results and increase costs. Two national surveys, the National Immunization Survey (NIS) and the NIS-Teen, were used to study the impact of survey length, as stated by the interviewer, and inclusion of a topic of interest to respondents on response rates. The two studies included comparisons of the standard survey instruments to revised, condensed instruments. The NIS study also included variations of the standard survey with sections considered of interest for parental respondents, the Parental Concerns Module (PCM), which contained questions about parents' thoughts and beliefs about vaccinations. The outcomes of interest were differences in the response rates and resulting survey costs in each of the study conditions. The shortened instruments resulted in higher response rates compared to both the standard instruments and the instruments including the PCM and reduced the overall time needed to complete an interview. Based on these results, the NIS and NIS-Teen questionnaires were both shortened.