The purpose of the study was to evaluate the effectiveness of GPS in accomplishing the aims of victim protection via contact deterrence during the pretrial period, resulting in an improved quality of life for the victims as well as their greater participation in criminal justice proceedings. The second aim was to assess whether Global Positioning System (GPS) enrollment is associated with deterrence in the long term, as measured by lower likelihood of re-arrest during a one-year follow- up period. The study also attempted to provide
an integrated picture of the ancillary benefits, advantages and liabilities resulting from the use of GPS in domestic violence cases.
The study is comprised of two parts: first, a web-based survey of pretrial service agencies in the United States was conducted to learn how electronic monitoring technologies are used in their operations, with a specific emphasis on applications of Global Positioning System (GPS) to address domestic violence (DV) cases.
Second, a quasi-experimental design was applied to the analysis of quantitative data collected by large and established programs to study GPS systems' effectiveness in deterring program violations (including contact violations) while being monitored, and in reducing re-arrest during both the monitoring period and a one-year follow-up period. Three GPS-using jurisdictions participated in the quantitative component of the study, referred to here as the Midwest site, the West site, and the South site. Agencies participating in this part of the study were all using active GPS platforms. The agencies were selected after consulting with a variety of agencies nationwide about their program design, caseload size, data quality, and data accessibility. The selected sites varied in terms of overriding philosophy, enrollment criteria, and staffing structure, enabling inferences to be drawn about the impact of variations in implementation styles. The agencies selected for the impact study had been operating a GPS program for DV defendants for at least three years, and offered access to offender data for a period of at least one year following their exit from all supervision related to the instant offense (i.e., the incident that resulted in the charge(s) that qualified them for program enrollment). Because the agencies exercise varying degrees of restrictiveness and transparency in their supervision practices, site differences may account for some outcome differences (both in the short and long terms); consequently, agency level effects will be examined in the context of a combined site data analysis. The method of data collection in the three sites also varied: in the two sites, Midwest and West, the principal investigators collected their own data, whereas in South they used administrative data for the analyses. The study looks at impact in the short-term (during the enrollment period) and in the long-term (during a one year follow-up period).
The treatment and control groups were constructed in different ways for the Midwest, West, and South sites. A detailed discussion of this can be found in Chapter 2, Section B of the final report for this study (Erez, Ibarra, Bales, and Gur, 2012, NCJ 238910).
For the web-based survey (Part 1), agencies known to use Global Positioning System (GPS) were contacted using a national list provided by an electronic monitoring (EM) expert consultant. In addition, two organizations for pretrial agencies, the Pretrial Justice Institute (PJI) and American Probation and Parole Association (APPA), sent an email with an embedded link inviting their members to participate in the web-based survey. The survey received responses from 616 individuals (Part 1) representing agencies in 43 states, the District of Columbia, and Puerto Rico.
In the Midwest Site Data (Part 2), a total of 2,052 defendants referred to the GPS program over a two-year period (2006-2008) comprised the sample; they spent the pretrial period either on GPS, on radio frequency (RF), in jail, or were bonded out without any form of EM.
In the South Site Data (Part 3), a total of 604 defendants with domestic violence (DV) charges were selected from jail booking and release data over two years (2008-2009), and these data were supplemented with information found in the records of the pretrial agency that monitored the defendants during the pretrial period. This sample was distributed across four groups (177 in the GPS group, 167 in the RF group, 42 in the Jail group, and 218 in the Bond without EM group).
In the West Site Data (Part 4), a total of 1,000 defendants who were referred to GPS over sixty-four months (October 2001 - January 2007) comprised the sample in this site. These defendants were placed on GPS, kept in jail or released on bond without any form of EM. Cases were drawn from the GPS program's database, in which information from judges' orders (including referrals) had been entered, between October 2001 and January 2007, yielding the following samples: 500 GPS cases (or 100 percent of defendants who were referred and hooked up) and 500 non-GPS cases (or 74 percent of defendants who were referred but not hooked up, i.e., who remained in jail or were bonded out without spending any time on GPS).
A more detailed discussion of the construction of the samples for the quasi-experimental design part of the study can be found in Chapter 2 Section B of the final report (Erez, Ibarra, Bales, and Gur, 2012, NCJ 238910).
All pre-trial service agencies in the United States (Web-Based Survey, Part 1).
All defendants referred to the GPS program in the Midwest Site over a two-year period, 2006-2008 (Part 2).
All jail bookings that occurred from January 2008 to 2009 in which DV was one of the arrest charges at South Site (Part 3).
All defendants referred to GPS in West Site over sixty-four months, Oct 2001 - Jan 2007, (Part 4).
Court and jail records
Electronic monitoring program databases
administrative records data,
The web-based survey (Parts 1) posed Likert scale, mutually exclusive, and open-ended questions aimed
at documenting a number of factors related to the implementation of electronic monitoring (EM) programs in general and specifically for GPS for domestic violence (DV) programs. The questions addressed program attributes, issues of technology, vendors and training, respondents'
views about and experiences with programs utilizing GPS for DV during pretrial, issues pertaining to victims and lastly, defendant-relevant factors. The Web-Based Survey Data (Part 1) includes 236 variables from the survey, including calculated variables and recodes.
The quasi-experimental design component of the study (Parts 2-4) included treatment, impact, and control variables. Treatment was measured by exposure to GPS and number of days on the program. Impact measures included short-term arrests and contact violations as well as long-term arrests. Control variables included demographic characteristics (such as age, gender, race, education, marital status, etc.), severity of instant offense, offense history, and legal measures and indicators (such as conviction for the current offense, type of sentence, time served, etc.). Midwest Site Data (Part 2) includes 20 variables, South Site Data (Part 3) includes 21 variables, and West Site Data (Part 4) includes 26 variables.
Several Likert-type scales were used (Part 1)