The data analyzed were drawn from the New York State Department of Correctional Services and describe all inmates under the jurisdiction of the New York prison system during a 1-year period (1983), along with characteristics of the facilities where these prisoners are housed. Separate subanalyses examine inmates' odds of assault involvement and severity of assault incidents. Results indicate that inmate attributes influence the odds of assault involvement but not the severity of assaults. Prison-level factors influence both the odds of assault involvement and severity. The importance of studying variables at multiple levels is emphasized. 2 figures, 7 tables, notes, and 53 references. (Author abstract modified)