Organizational factors that help shape the demands and resources available to each agency are examined. These include external factors (socioeconomic forces, legal influences, and political factors) and internal factors (organizational responsibilities and resources). Four component activities of on-scene investigations are discussed: coordination and control; fire scene investigation, including physical, testimonial, and other evidence collection; special investigative issues; and report preparation. The impact of deciding where to allocate scarce resources on arson investigation thoroughness in the eight sites is examined. Standard followup practices, type of personnel involved, and type of followup results obtained are discussed. The impact of the organizational profile on the investigation, the source and frequency of observed deficiencies, and personnel issues (including staffing arrangements, recruiting, training, and retention) are explored. Finally, the need to improve arson unit management at four operational levels -- system, departmental, unit, and case -- is emphasized. One chart and 51 tables are included.