The nature of activities in which institutional researchers are involved in different institutional and organizational settings was studied. In order to characterize the practice of institutional research in various institutional settings, a taxonomy of institutional research activity areas was developed. A 114-item taxonomy was developed that was divided into 13 categories. The taxonomy was incorporated into the Professional Development Needs Assessment Survey (PDNAS). For each item, respondents were asked to indicate whether the activity was one in which they or their office had performed in the past 2 years. In the spring of 1981, the PDNAS was mailed to all members of the Association of Institutional Research. Approximately 40 percent of the members (701 persons) completed the survey, and the database for this survey consisted of 295 responses. Factor analysis was used to validate a 92-item taxonomy of institutional research activities. Through discriminant analyses, the study provides an operational definition of institutional research as it is practiced in institutional and organizational settings that vary according to institutional type, offices to whom institutional research offices report, time period in which institutional research offices were established, and full-time-equivalent size of institutional research staff. The results further suggest that the activities may be a function of the diversity and level of sophistication of the research staff. Possible future directions for institutional research are noted. A bibliography is appended. (SW)