Almost all survey interviews are now conducted using some type of computer-assisted interviewing (CAI) software. However, unless CAI instrument design and usability are considered, even the most carefully worded questions can yield questionable data. Ample evidence exists that usability is enhanced when user needs are considered early and continuously throughout the software development process. In the development of complex computer-assisted interviewing instruments, this means bringing interviewers into the development process as soon as possible. But developing complex CAI applications poses special demands, because interviewers are often highly diverse in computer skills and geographically scattered, which makes obtaining their input more challenging. This paper discusses different approaches that have been used to addres instrument design and to incorporate user-centered design principles into thedevelopment of complex computer assisted personal interviewing (CAPI) instruments.Examples from the Consumer Expenditure Quarterly Interview and the Commodity & Services Pricing survey will be cited. Besides describing possible approaches that could be used to encourage user-centered design, this paper will also present evaluation instruments and methods that have been used to quantify the success of usability-design efforts.