This report describes a technique developed as part of the As Parents Grow Older (APGO) Project at the University of Michigan Institute of Gerontology which uses audiotape recordings in the analysis and evaluation of group intervention programs such as those designed to aid middle-aged adults in understanding and caring for their aging parents and relatives. The relationship between intervention program design and program evaluation is briefly discussed. Two evaluation methods, content coding (the analysis of audiotapes for information exchanged during group interactions) and process coding (the analysis of group atmosphere and interpersonal behavior during group interactions), are described in detail, and the units of measure and procedures involved in process coding are reviewed. Some possible applications of the two methods of coding are then discussed. Four figures, including examples of content coding and process coding instruments, accompany the text. (JL)