Evaluating a Lethality Scale for the Seattle Police Department Domestic Violence Unit, 1995-1997

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.

Tags: crime-prediction, criminal-histories, domestic-violence, felony-offenses, misdemeanor-offenses, program-evaluation, risk-assessment
Organization: Department of Justice