one common basis for distinguishing types of homicide involves their motive. Typical motives and circumstances surrounding homicides include trivial altercations, jealousy, revenge, romantic triangles, robbery, sexual assault, burglary, and disputes in drug transactions. These motives are often subclassified to differentiate between two general types of homicides: “expressive” and “instrumental” homicides.

Using narrative accounts of homicides in Los Angeles over the twentieth century and the national Supplementary Homicide Reports (SHR), this chapter examines the episodal nature and structure of expressive and instrumental homicides. Descriptive case accounts are analyzed to identify patterns in the transactions that underlie the most common types of expressive homicides (i.e., confrontational disputes among male offenders) and instrumental killings (i.e., robbery-homicides). Qualitative Comparative Analysis (QCA) is used on the SHR data to determine whether instrumental and expressive homicides are qualitatively different in their structures (i.e., combinations of offender, victim, and situational characteristics). We do this empirically by identifying the most prevalent combinations of individual and situational elements unique to each type of homicide, as well as those common to both, through QCA's systematic process of holistic comparison.

Instrumental and Expressive Crimes

Although not without its critics (e.g., Felson 1993; Polk 1994), the distinction between instrumental and expressive crimes has been widely used in criminological research. Instrumental crimes are those conducted for explicit, future goals (such as to acquire money or improve one's social position), whereas expressive offenses are often unplanned acts of anger, rage, or frustration (see Block 1976; Block and Christakos 1995; Block and Zimring 1973; Decker 1993; 1996; Siegel 1998).