The ROI of Pretrial Electronic Monitoring: Data from US Programs

Introduction: The Economic Logic of Pretrial EM

Pretrial detention costs US taxpayers an estimated $14 billion annually. The average daily cost of housing a jail inmate ranges from $137 (BJS national average) to over $550 in high-cost jurisdictions like New York City. Meanwhile, electronic monitoring costs $5-15/day — a 90-98% cost reduction per defendant.

But raw per-day cost comparison overstates EM’s ROI if the analysis ignores who is being monitored. EM only generates savings when it diverts defendants who would otherwise be detained. If EM is applied to defendants who would have been released without conditions, it adds cost without reducing jail use. This whitepaper examines actual program outcomes to quantify the real-world ROI of pretrial electronic monitoring.

Program Data: Washington DC

The DC Pretrial Services Agency (PSA) operates one of the oldest and most studied pretrial EM programs in the US. The Urban Institute conducted a multi-year evaluation with these findings:

Cost Data

Metric	Value
Total EM cost per participant/year	$750
Local jail savings per participant/year	$580
Federal savings per participant/year	$920
Net savings per participant/year	$750
Cost of jail detention/year (DC average)	$55,000+

Outcome Data

• Court appearance rate: 88% for GPS-monitored defendants
• Pretrial rearrest reduction: 24% compared to baseline expectations
• Comparison to detention: EM participants were less likely to be rearrested than defendants who were detained and later released — suggesting that maintaining community ties during the pretrial period has a protective effect

ROI Calculation

For each defendant diverted from detention to EM:

• Jail cost avoided: $55,000/year
• EM cost incurred: $750/year
• Net savings: $54,250/year per diverted defendant
• ROI: 7,133%

Note: This ROI applies only to defendants who would have been detained. DC’s program targets moderate-to-high risk defendants, ensuring that EM substitutes for detention rather than supplementing release.

Program Data: Cook County (Chicago)

Cook County’s 2017 bail reform provided a natural experiment. The elimination of cash bail for most misdemeanor and low-level felony cases created a comparison between defendants released with EM conditions and defendants released unconditionally.

Key Findings

Outcome	Unconditional Release	EM Release	Difference
Failure to appear rate	Baseline	-10.6 pp	EM reduced FTA
New pretrial criminal cases	Baseline	-7.4 pp	EM reduced crime

Cost-Effectiveness Analysis

The cost of a single failure to appear includes: bench warrant issuance, law enforcement fugitive apprehension efforts, rebooking/processing costs, and potential additional pretrial detention. The total estimated cost of an FTA ranges from $1,800 to $15,000 depending on jurisdiction and case severity.

With a 10.6 percentage point FTA reduction and an average FTA cost of $5,000, the savings per 100 monitored defendants = 10.6 × $5,000 = $53,000. At an EM cost of roughly $10/day × 90 days × 100 defendants = $90,000, the break-even occurs when EM prevents FTA costs of approximately $90,000 — or roughly 18 FTAs. Since the data shows EM prevents approximately 10.6 FTAs per 100 defendants, the program reaches break-even at FTA costs above approximately $8,500 per incident — a threshold that many jurisdictions exceed when accounting for full system costs.

Program Data: San Francisco

San Francisco’s EM program demonstrated scalability:

Year	EM Cases	Court Appearance Rate
2017	75	87%
2018	350	86%
2019	800	85%
2020	1,200	85%
2021	1,650	86%

Key insight: court appearance rates remained stable even as the program expanded 20x. This counters the common concern that EM programs degrade in quality as they scale. San Francisco’s experience suggests that operational processes — not technology — determine outcome quality.

Composite ROI Model

Based on the data from these three programs and supplementary research, here is a composite ROI model for a typical pretrial EM program:

Assumptions

• 200 defendants monitored per year
• Average monitoring duration: 90 days
• 60% are true detention diversions (would have been detained without EM)
• 40% are supervised release additions (would have been released without conditions)
• EM cost: $10/day per defendant
• Jail cost: $175/day (national mid-range)

Annual Cost Analysis

Item	Calculation	Amount
EM program cost (all 200 defendants)	200 × 90 days × $10/day	$180,000
Jail cost avoided (120 diverted defendants)	120 × 90 days × $175/day	$1,890,000
Net savings	$1,890,000 – $180,000	$1,710,000
ROI	$1,710,000 / $180,000	950%

Sensitivity Analysis

Even at conservative assumptions:

• If only 30% of EM defendants are true detention diversions → net savings = $765,000 (ROI = 425%)
• If jail costs are $100/day (low-cost jurisdiction) → net savings = $900,000 (ROI = 500%)
• If monitoring costs are $15/day (premium technology) → net savings = $1,620,000 (ROI = 600%)

Under all reasonable scenarios, pretrial EM programs generate positive ROI — provided that the program is designed as a detention alternative and not merely an add-on to existing release conditions.

The Net-Widening Risk

The single largest threat to pretrial EM ROI is net-widening. If EM is applied to defendants who would have been released without conditions, the program adds the cost of monitoring without avoiding any detention costs.

How to prevent net-widening:

• Use validated risk assessment: Apply EM only to defendants whose PSA or other risk scores indicate they would otherwise be detained
• Track the counterfactual: For each defendant placed on EM, document whether the alternative was detention or unconditional release
• Monitor jail population trends: If the jail population doesn’t decrease as EM enrollment increases, net-widening is occurring
• Set enrollment criteria: Define specific charge categories and risk scores that qualify for EM, and enforce them

Technology and ROI

Technology selection affects program ROI through two channels: device/service cost and operational efficiency.

• One-piece vs two-piece devices: One-piece GPS monitors like the CO-EYE ONE eliminate the separate body-worn transmitter, reducing device costs and simplifying installation/recovery logistics.
• Battery life: Devices with longer battery life (40+ hours for CO-EYE ONE) reduce compliance calls related to dead batteries — each compliance call costs the program staff time and potentially a field visit.
• False alert rates: Optical fiber anti-tamper produces zero false positives for tamper events, eliminating the staff time wasted investigating false alarms. See our analysis: Understanding Ankle Monitor False Alert Rates.
• Tiered technology: Using smartphone monitoring (e.g., CO-EYE AMClient) for low-risk defendants and GPS ankle monitors for high-risk defendants optimizes cost across the caseload.

Conclusion

Pretrial electronic monitoring generates substantial positive ROI when designed as a detention alternative. The evidence from DC ($750/year vs $55,000/year for detention), Cook County (10.6pp FTA reduction, 7.4pp crime reduction), and San Francisco (20x scale-up with stable outcomes) is consistent: GPS monitoring costs 90-98% less than detention while maintaining or improving public safety outcomes.

The key variable is program design, not technology. Risk-assessment-driven enrollment, tiered technology, and rigorous net-widening prevention determine whether a program achieves the 500-7,000% ROI that is theoretically available, or becomes an expensive supplement to existing release practices.

For program design guidance, see our Pretrial Electronic Monitoring Guide. For technology specifications and pricing, visit the CO-EYE product pages or contact REFINE Technologies.