The research used a data on all single-victim, single-offender homicides for 1990-94, providing that no data on relevant variables were missing. Results revealed that instrumental and expressive homicides had both common and unique social contexts, but the vast majority of homicide incidents involved combinations of individual and situational factors that were common in both general types of homicides. Wide variability also existed in the prevalence of unique and common components among subtypes of instrumental homicides, including rape, prostitution, and robbery murders, and expressive homicides, including lovers' triangles, brawls, and arguments. Findings indicated that contrary to prevailing assumptions, instrumental and expressive homicides typically share the same particular combinations of offender, victim, and situational characteristics. Findings also indicated that the quantitative comparative analysis approach has enormous potential for studying crime across a variety of contexts. Tables, figures, and 44 references (Author abstract modified)