The core CPES questionnaire was based largely on the World Health Organization's (WHO) expanded version of the Composite International Diagnostic Interview (CIDI) developed for the World Mental Health (WMH) Survey Initiative, the WMH-CIDI (Kessler and Üstün, 2004). Ronald Kessler, Professor of Health Care Policy at Harvard Medical School and Chair of the CIDI Advisory Committee, provided the background and history of the development of the CIDI, the instrument that was used to collect the diagnostic data in the CPES. You may view a 22-minute video of his presentation.
All three surveys used a modified version of the WMH-CIDI, which had been developed over the course of more than a year by an international group of collaborators, as described by Kessler and Üstün (2004). The design of the WMH-CIDI involved modifications and additions to the existing WHO-CIDI. The CIDI was an expansion of the Diagnostic Interview Schedule (DIS), the first standardized psychiatric diagnostic interview developed for administration by lay interviewers. The CIDI was designed to produce diagnoses based on WHO International Classification of Disease (ICD) criteria, while diagnoses from the DIS could only be made based on American Psychiatric Association (APA) Diagnostic and Statistical Manual (DSM) of Mental Disorders criteria. As summarized by Wittchen (1994), Kessler and Üstün (2004), DIS and CIDI validity studies suggest that there is a significant correlation between diagnoses based on data collected using the DIS and CIDI and diagnoses made by clinicians who reinterview a sample of respondents. Researchers who were involved in the design of the WMH-CIDI were interested in continuing to enhance the quality of survey measurement. As part of the WMH-CIDI development process, debriefing interviews were conducted with CIDI respondents and several methodological improvements were made to the instrument based on findings from the debriefing interviews. See Kessler et al. (2000) and Kessler and Üstün (2004) for a detailed discussion of the content additions and methodological enhancements that were incorporated in the WMH-CIDI instrument. The WMH and CPES questionnaires were administered using computer-assisted interviewing (CAI). The instruments were programmed using Blaise, a CAI software package developed by Statistics Netherlands and used by many government statistical agencies and large survey research organizations worldwide (Blaise Survey Processing System, Version 4.5). Blaise software is specifically designed to accommodate very complicated questionnaire skip patterns and sub-sampling algorithms. Potential drawbacks of using Blaise include its cost and the requirement for highly trained programmers to write the code for complex surveys.
The questionnaire design and testing phase for each project spanned approximately one year. The initial goal was to finalize the NCS-R questionnaire first, particularly the psychiatric disorder sections, in order to make these sections available to NSAL and NLAAS. However, the time required to finalize the NCS-R questionnaire was lengthened because development of the NCS-R questionnaire and the World Mental Health Survey Initiative questionnaire occurred in tandem, resulting in many revisions to the core questionnaire over this period.