• Presentation

Same Respondents, Same Questions; Different Modes, Different Responses


Stockdale, J. D., Thornburg, V. E., & Aldridge, A. P. (2008, May). Same Respondents, Same Questions; Different Modes, Different Responses. Presented at AAPOR 2008, New Orleans, LA.


Survey research shows in many instances that respondents report higher levels of sensitive behaviors during an in-person interview than during a telephone interview (Beck, et al., 2002; Woltman, et al., 1980). Specifically, researchers have found that respondents provide higher levels of alcohol, tobacco, and illicit drug use during in-person interviews, and report lower levels of those behaviors when a telephone interviewer asks the same set of questions. This “mode effect” is found when comparing different sets of CAPI and CATI respondents, and our paper examines whether this mode effect remains salient during a longitudinal survey using the same set of respondents. This paper addresses this question by analyzing data collected from the Screening, Brief Intervention, Referral and Treatment (SBIRT) study, funded by the Center for Substance Abuse Treatment in the Substance Abuse and Mental Health Services Administration. Data were analyzed from a CAPI baseline interview and a CATI six month follow up interview with the same respondents and the same questions. Findings show that a significant number of respondents who answered that they had used alcohol or illicit drugs in their lifetime during the CAPI baseline interview answered that they had not used those drugs during their lifetime in the CATI follow-up interview. This paper further investigates the established mode effect between CATI and CAPI interviewing using a within subjects design. Based on our findings, we compare the accuracy of prevalence data collected from a CAPI and CATI study. We also take a look at other mediating factors that may play a role in diminishing this mode effect.