This study represents an effort to develop an observational instrument to assess a correctional officer's behavior, and to evaluate officer training programs. A list of 73 inmate behaviors to which the officer might respond was assembled. The most relevant, significant, and most often occurring inmate behaviors were selected. Six judges with orientations in psychology and corrections rated 4 basic officer responses (reinforced, ignored, terminated, punished) according to their effectiveness in modifying each of the 73 inmate behaviors. This procedure established which response of the officer was most desirable. Agreement between judges and mean ratings for each response were recorded in tables titled the Standardized Response Index. The observation instrument was then constructed and tested for reliability. Information recorded by the observer was: the interaction number, verbal contact (verbal content and tone), type of interaction, type person(s) and number of persons interacting, and officer's response. Information to determine observer reliability was collected by 2 pairs of observers. Overall, the reliabilities of the indices were moderate to high (+.47 to +.97). Internal validity was supported by data collected for 15 officers which supported three important assumptions. External validity was not clearly determined. (Author/DB)