This paper recognizes the increasing burden being placed on those who design and program instruments for Computer-Assisted Telephone Interviewing (CATI) systems, and proposes certain enhancements to CAT1 instrument management capabilities that should be useful in easing this burden. The suggested approach for incorporating these features is to use a design based on the properties of the logical structure of instruments, many of which are described. An attempt is made to demonstrate that this approach results in a reliable, extendable and comprehensive CAT1 system design.