Methodological studies of the Composite International Diagnostic Interview (CIDI) in the US National Comorbidity Survey (NCS)

This paper reports the results of methodological studies carried out in conjunction with the US National Comorbidity Survey (NCS) to evaluate Version 1.0 of the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI). These studies relied on recent survey data collection methodology literature to investigate problems regarding question comprehension, instruction comprehension, respondent motivation to report accurately, and regarding the limits of respondent ability to report accurately. Insights and strategies developed by survey methodologists were used to modify the CIDI in an effort to address these problems. The paper describes these strategies and methodological studies that evaluated their effects, including a clinical reappraisal study and a field experiment that evaluated the impact of question modifications on prevalence estimates. The paper closes with a discussion of remaining methodological problems with the CIDI and potentially useful future studies that might be able to develop solutions to these problems. tured instrument like the CIDI in the NCS because of the large sample size, the enormous geographic dispersion of the sample, and the prohibitive costs and logistic complications of the study. The NCS was the first large-scale general population survey to administer the CIDI in the United States. Although WHO CIDI Field Trials carried out prior to the NCS documented good performance of the instrument (Wittchen 1994), the field trials were conducted largely in clinical samples and administered in clinical settings. As a result, we considered it very important to carry out pretests before using the instrument in a community sample. As described more fully below, the NCS pretests were guided by the literature on survey data collection methodology (e.g. Bradburn et al. 1979; Moss and 33