Past research and experience have documented considerable variation in what is learned and applied in staff inservice efforts, even for participants in the same workshop. For a study which set out to explain such variation, pre- and post-workshop questionnaires were completed by 349 staff (three-fourths of whom were teachers) who participated in 36 teacher-initiated, inservice projects. Participants' ratings of five inservice outcomes were regressed on, and correlated with, their background characteristics, their psychological and professional traits, their school and community characteristics, their school climate, and features of their workshops. All variables combined account for 85 percent of the variance in the inservice outcome measures. Approximately half of this variance is accounted for by the staff and school characteristics, and the remaining half by the climate and workshop features. These results indicate that complex interactions of many staff, contextual, and workshop factors affect the outcomes of staff inservice. Many of these factors can be influenced by workshop designers. (Author/JD)