Initially, two major data sets on policing, both of which relied on observational data, were compared; a merged data file contains the common measures used. The distribution of dispositions in police contacts with juveniles and domestic disputes were compared across the two data sets. The evidence suggests that, in the first example, two variations lay in the distribution of types of juvenile cases handled by the police and the way the police-juvenile encounter began. With regard to domestic disputes, the percentage of arrests was similar in both data sets; two differences lay in the percentage of arrests involving married disputants and the number of cases in which the complainant requested an arrest be made. The observational data currently available does not indicate whether the differences noted result from trends in police decisionmaking, departmental differences, or regional variations. Future large scale observational studies of policing should be conducted in the same department and same areas as either or both of the previous data collections. The current project also assesses similarities and differences between patrol officer activity in the two existing data sets in terms of incident type by shift, day of the week, size of the department, and neighborhood. Data was collected on how observed police spend their time and the closeness of supervision of patrol officers. All future research suggested in this paper would involve some observational component in order to obtain a realistic picture of police routines. 2 notes, 13 tables.