Criminal Justice Outcomes in Intimate and Non-intimate Partner Homicide Cases

4. Results (cont'd)

4.2 Multivariate analysis: Isolating the effects of intimacy in criminal law

Because the objective here is to compare the treatment of those who killed intimate partners to the treatment received by those who killed victims with whom they shared more distant relationships, a reduced sample is used in this part of the analysis for two reasons. First, intimate partner homicides rarely involve more than one accused and one victim (Silverman & Kennedy, 1987, 1993). For example, in the Toronto data, 98 percent of those accused of killing intimate partners acted alone whereas 82 percent of the 907 accused of killing other types of victims acted alone. Therefore, while the majority of homicides involve lone offenders, this is almost exclusively the situation in intimate partner homicides. With respect to the number of victims, the proportion of intimate partner and non-intimate partner homicides that involved the killing of more than one victim is small, but similar (4% and 5% respectively). Thus, in order to compare similar types of killings, the reduced sample is restricted to cases that involved one accused and one victim. Second, by virtue of its definition, the category ‘intimate partner’ is comprised primarily of adults. In the Toronto sample, the youngest accused person who killed an intimate partner was 19 years of age while the youngest victim killed by an intimate partner was 17 years of age. Again, to ensure that similar types of cases are compared, the reduced sample is restricted to those victims who were greater than or equal to these ages. The final reduced sample used in the multivariate analysis, then, was 914 cases.

The control variables used in the multivariate analyses are similar to those examined in the bivariate analysis. Of particular interest, however, are the variables that significantly distinguished between intimate partner and non-intimate partner homicide at the bivariate level. For example, there were significant differences between the two types of homicide based on the accused person’s prior record, gender, age, employment status, marital status and psychiatric history. In addition, the victim’s gender, age, prior criminal record, employment and marital status as well as location and method of killing also distinguished between the two types of homicide. It is important, then, to control for these factors in the multivariate analysis to allow for an examination of the independent effects of intimacy on court outcomes.[30]

Results are presented in Table 4.8 for a series of multivariate models. Models 1 through 7 show the results of the logistic regression analysis that was used to examine the odds of being in the focal group compared to the reference group based on particular characteristics (only the odds are shown here[31]; see Appendix D for the full results for each model). The final column – Model 8 – shows the multiple regression coefficients for length of sentence. Findings for each stage of the process for the key independent variables – victim-accused relationship, the year the case entered the court, and gender – are discussed first.[32]

With respect to the entry point of the criminal process, Model 1 demonstrates that those accused of killing intimate partners were less likely to be charged with first-degree murder than those accused of killing victims with whom they shared more distant relationships. Model 2 shows that accused persons in intimate partner homicides were less likely to have their cases resolved at trial than those who killed other types of victims. In other words, cases of intimate partner homicide were more likely to be disposed of by guilty plea than cases of non-intimate partner homicide. However, among those cases that were resolved at trial, Model 3 demonstrates that accused persons who killed intimate partners were significantly more likely to be convicted at this stage than those who killed non-intimate partners (see Box 4). Among those acquitted (Model 4), however, there were no differences in the type of acquittal – not guilty versus not criminally responsible by reason of mental disorder.[33]


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