ABSTRACT Despite growth in the use of electronic monitoring (EM), and Global Positioning Satellite (GPS) tracking in particular over the last 20 years, limited research has examined the effectiveness of these approaches on community supervision outcomes (e.g. likelihood of failure on community supervision). This study makes use of data from over 59,000 probation cases collected over a 40-year time span in a midwestern state. Using Propensity Score Matching (PSM), the study compares the rates of unsuccessful sentence completion among those who were supervised with and without any EM (and also GPS specifically). Results reveal that after matching cases on a variety of relevant controls (e.g. demographics, risk level, current offense type), those receiving EM while on probation were significantly more likely to fail to complete their term of supervision, with similar results for those who received GPS, specifically. Limitations of the study and implications for the use of EM/GPS with probationers as a potential alternative to prison are discussed.