DOI: 10.3886/icpsr03026.v1
title: Evaluating a Lethality Scale for the Seattle Police Department Domestic Violence Unit, 1995-1997
title: Version 1

description: The specific aim of this project was to evaluate the usefulness of the Seattle Police Department's (SPD) Lethality Scale in identifying misdemeanor cases that might be high risk for escalating violence and subsequent felony incidents. Data provide information on 11,972 unique couples with incidents occurring between January 1, 1995, and December 31, 1997, involving intimate couples in which the suspect was at least 18 years old and the victim was at least 16, with no age restriction for cases referred to the juvenile division. The researchers reformatted the Domestic Violence Unit's (DVU) database to reflect a three-year history of violence between unique couple members. Only intimate couples were considered, meaning suspects and victims who were married, divorced, had a child in common, or were dating. The Lethality Scale was derived from the data in the DVU database. It was composed of six incident characteristic components (offense score, weapon score, location score, injury score, personal score, and incident/other score) with varying values that contributed to an overall score. The Total Lethality Score was the sum of the values from these six components. The lethality score referred to an individual only and did not reflect information about other people involved in the incident. To interpret the score, the DVU specified a period of time--for example, six months--and computed lethality score values for every person involved in an incident during this period. Information on individuals with a Total Lethality Score over a certain cut-off was printed and reviewed by a detective. Data are provided for up to 25 incidents per unique couple. Incident variables in the dataset provide information on number of persons involved in the incident, time and weekday of the incident, beat, precinct, census tract, and place where the incident occurred, type of primary and secondary offenses, if a warrant was served, charges brought, final disposition, weapon type used, arrests made, court order information, if evidence was collected, if statements or photos were taken by the DVU, and sergeant action. Dates were converted to time intervals and provide the number of days between the incident date and the date the file was sent to the prosecutor, the date charges were brought, and the date the case was officially closed. Time intervals were also calculated for days between each incident for that couple. Personal information on the two persons in a couple includes age, gender, injuries and treatment, relationship and cohabitation status of the individuals, pregnancy status of each individual, alcohol and drug use at the time of the incident, and role of the individual in the incident (victim, suspect, victim/suspect). Lethality scale scores are included as well as the number of incidents in which the unique couple was involved in 1995 and 1996, and 1989 median household income for the census tract.
description: The majority of domestic violence incidents involve misdemeanor cases, but Seattle Police Department (SPD) detectives were routinely assigned to follow only felony incidents. Since assigning detective follow-up for all misdemeanor cases was not practical, the SPD created the Lethality Scale to screen misdemeanor domestic violence incidents for assignment to detectives for follow-up. The specific aim of this project was to evaluate the usefulness of the Seattle Police Department's (SPD) Lethality Scale in identifying misdemeanor cases that might be high risk for escalating violence and subsequent felony incidents. However, it should be noted that the term "Lethality Scale" is a misnomer since the scale did not cover only lethal outcomes.
description: Data provide information on 11,972 unique couples with incidents occurring between January 1, 1995, and December 31, 1997, involving intimate couples in which the suspect was at least 18 years old and the victim was at least 16, with no age restriction for cases referred to the juvenile division. The researchers reformatted the Domestic Violence Unit's (DVU) database to reflect a three-year history of violence between unique couple members. Only intimate couples were considered, meaning suspects and victims who were married, divorced, had a child in common, or were dating. An individual's role as suspect or victim could change from incident to incident, meaning in one incident the individual could be a victim and in the next incident, the individual could be a suspect. A "strange couple" designation was given for incidents without a clearly defined victim and a clearly defined suspect. The Lethality Scale was derived from the data in the DVU database. It was composed of six incident characteristic components (offense score, weapon score, location score, injury score, personal score, and incident/other score) with varying values that contributed to an overall score. The Total Lethality Score was the sum of the values from these six components. The lethality score referred to an individual only and did not reflect information about other people involved in the incident. To interpret the score, the DVU specified a period of time--for example, six months--and computed lethality score values for every person involved in an incident during this period. An individual's Total Six Month Lethality Score was the sum of the Total Lethality Scores for every individual involved in an incident over the period of six months. Information on individuals with a Total Six Month Lethality Score over a certain cut-off was printed and reviewed by a detective. The researchers simulated the DVU's approach using two years of DVU data from the database to evaluate the predictive ability of the Lethality Scale.
description: Data are provided for up to 25 incidents per unique couple. Incident variables in the dataset provide information on number of persons involved in the incident, time and weekday of the incident, beat, precinct, census tract, and place where the incident occurred, type of primary and secondary offenses, if a warrant was served, charges brought, final disposition, weapon type used, arrests made, court order information, if evidence was collected, if statements or photos were taken by the DVU, and sergeant action. Dates were converted to time intervals and provide the number of days between the incident date and the date the file was sent to the prosecutor, the date charges were brought, and the date the case was officially closed. Time intervals were also calculated for days between each incident for that couple. Personal information on the two persons in a couple includes age, gender, injuries and treatment, relationship and cohabitation status of the individuals, pregnancy status of each individual, alcohol and drug use at the time of the incident, and role of the individual in the incident (victim, suspect, victim/suspect). Lethality scale scores are included as well as the number of incidents in which the unique couple was involved in 1995 and 1996, and 1989 median household income for the census tract.
description: ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection: Standardized missing values.; Checked for undocumented or out-of-range codes..
description: Presence of Common Scales: None.
description: Response Rates: Not applicable.
description: Datasets: 
 
 DS1: Dataset
description: These data are from Subproject 3 of the grant. The evaluation concluded that the scale, with all the scoring and weighting, reflected recidivism only and could not be modified to be a better predictive tool.
description: All reported misdemeanor domestic violence incidents in Seattle from 1995-1997.