The case, honestly made
Claim the effect the evidence supports
Electronic monitoring has real, replicated effects. They are not the effects people assume, and a case built on the wrong one loses the room to the first person who has read the literature.
What the evidence says monitoring actually does
A reviewer is going to do this reading anyway. Doing it first, in public, is the only version of this that survives.
| Study | Population | Finding |
|---|---|---|
| Bales et al., NIJ 2010 (Florida)[22] | More than 5,000 monitored against more than 266,000 | Electronic monitoring reduced the risk of supervision failure by 31%. It does not measure new sexual offending, and is frequently miscited as if it does. |
| Gies et al., NIJ 2012 (California)[23] | 516, one year | Sex-crime rearrest 2.7% under GPS against 5.0% without; reconviction 1.9% against 4.3%. Not statistically significant is how the DOJ SMART Office reports both of the California GPS differences above.[4] |
| Turner et al., 2015 (California)[24] | 94 against 91, one year | New sex crime convictions 1.1% against 1.1% - identical. Absconding 2.1% against 9.9%; failure to register 3.2% against 13.2%. |
| Zgoba & Mitchell, 2021 meta-analysis[25] | 18 studies, 474,640 people | No statistically significant effect of registration and notification on recidivism, across all specifications. |
| Duwe et al., 2008 (Minnesota) Duwe, Donnay & Tewksbury (2008), Criminal Justice and Behavior 35(4) | 224 reoffenses | Not one would have been prevented by a residency restriction. 79% of reoffenders knew the victim beforehand. |
The defensible synthesis
Electronic monitoring has real, replicated effects on absconding, registration compliance and supervision failure, and weak-to-null measured effects on new sexual offending. Claim the first. Do not claim the second - the study that tested new sex convictions in a matched design found 2.1% against 9.9% was the absconding rate for GPS-supervised against comparison cases, and failure to register ran 3.2% against 13.2% - while new sex crime convictions were 1.1% in both groups.[24]
The California GPS result in row two is the one most often quoted the other way, and it should not be. The direction is favorable, but not statistically significant is how the DOJ SMART Office reports both of the California GPS differences above.[4] An earlier version of this page printed those two comparisons without that qualification, which invited exactly the reading the study does not support. A difference the authors could not distinguish from chance is not a result to build a pitch on.
This is a live argument rather than a fatal one. Compliance and absconding effects are worth money to a supervising agency on their own terms, and the graduated design on alert tiers is aimed at a failure mode none of these studies' systems addressed.
Turner, Chamberlain, Jannetta & Hess (2015), Victims & Offenders
A small matched design, 94 against 91, over one year. It is the study that most directly tested new offending, and it found no difference.
DOJ SMART Office, SOMAPI ch. 8, restating Sandler, Freeman & Socia (2008), Psychology, Public Policy, and Law 14(4)
The direction of the effect is favorable; the study could not establish that it is real.
Zgoba & Mitchell (2021), Journal of Experimental Criminology. 18 studies, 474,640 individuals
A meta-analysis of 18 studies covering 474,640 people.
Bales et al., NIJ (2010), Florida electronic monitoring assessment
It measures supervision failure, not new sexual offending. It is frequently miscited as if it measured the latter.
How to say it
Two framings. Only one survives the room.
The difference is not tone. It is whether the first informed question ends the conversation.
Do not use
"This protects children from predators."
An informed reviewer answers with the first-time-offender figure - 94.1% of child molestation arrests are of first-time sex offenders.[4] - and the conversation is over. Worse, the correction happens in public, and everything else said afterwards is discounted.
That figure is the DOJ SMART Office's restatement of Sandler, Freeman and Socia, who analyzed two decades of New York State arrest data. It has been replicated in Florida by Levenson and Zgoba: 6.5% of Florida sex crime arrests involved someone with a prior sex crime conviction - that is 93.5% first-time.[5]
The framing is not wrong because it is ambitious. It is wrong because it is checkable, and it does not check out.
Use this
The operational framing
"A peer-reviewed study of Cook County found that 95.50% of monthly GPS monitoring alerts in Cook County were false, up from 57.79% under radio frequency.[17] A Tennessee audit found that 80% of alerts were never checked by officers in a Tennessee audit.[29] Agencies ignore that stream, with documented fatal consequences. This system makes zone alerts actionable by requiring cross-modality corroboration before escalation, and it does so without building the location database that current monitoring requires and that courts are increasingly hostile to."
Name the studies inside the pitch rather than asserting the numbers flatly. A figure with a jurisdiction and a method attached to it can be checked in the room, and the version of this sentence that stated the percentages bare invited the reviewer to ask where they came from before hearing the rest.
That claim is defensible, it addresses a documented operational failure, and it speaks to the person who actually holds the budget.
DOJ SMART Office, SOMAPI ch. 8, restating Sandler, Freeman & Socia (2008), Psychology, Public Policy, and Law 14(4)
The DOJ SMART Office restatement of Sandler, Freeman & Socia. A Florida replication found 93.5%.
Cost, and the twelve-month clock
$35.96 per day was the cost of GPS supervision against $27.45 for traditional supervision.Gies et al., NIJ (2012), California GPS supervision evaluation
The buried cost is the battery
365 charge cycles are all that NIJ Standard-1004.00 requires of battery service life - and federal guidance instructs participants to charge at least daily.[11][14]
At daily charging, 365 cycles is exactly twelve months. Any deployment plan longer than a year must budget device replacement, not recharging. This is the line most business cases in this category get wrong, and it is the one a procurement officer will find.
One point of attribution, because it will be checked. The once-daily charging instruction is carried in district-level participant handouts, not in the national Location Monitoring Reference Guide [14] - an earlier version of this page put it in the national guide. It is standard local practice rather than a national rule, which does not change the arithmetic and does change what can be cited for it.
The requirement on devices doubles the NIJ minimum for exactly this reason.
NIJ Standard-1004.00, Offender Tracking Systems, NCJ 249810
At daily charging that is exactly twelve months. Any deployment longer than a year budgets device replacement, not recharging.
Anchor infrastructure is a different curve
Anchors are mains-powered and fixed. No battery, long service life, no charging obligation, no compliance event when someone forgets. In exchange they need per-site installation and a working relationship with every school district and parks department in the coverage area.
That relationship is the real barrier to entry - and, if it is won, the real moat. It is also the largest unmodeled risk in the whole concept, which is why it sits at the top of open questions rather than being quietly assumed away here.
What this page is not
It is not a costed proposal. No unit price, no headcount, no total appears anywhere on this site, because an invented number is worse than an absent one - and because this is a design document rather than a bid. The two figures above are published evaluation costs, cited, and they are inputs to a business case rather than a business case.
How this works
1:09 · narrated · captioned · nothing here is sent anywhere when you press play. Prefer to read it? The transcript is below.
Transcript
| At | Section | What it says |
|---|---|---|
| 0:02 | What this page is | A reviewer is going to read this literature anyway. Doing it first, in public, is the only version that survives. Five published studies are set out as they found. |
| 0:12 | The effect to claim | Monitoring has real, replicated effects on absconding, registration compliance and supervision failure. In one matched study absconding ran two percent against nearly ten. |
| 0:23 | The effect not to claim | Its measured effect on new sexual offending is weak to null. In that same study new sex crime convictions were identical in both groups. Claim the first finding, never the second. |
| 0:34 | How to say it | So do not pitch this as protecting children from predators. That claim is checkable and does not check out. Pitch the documented operational failure instead. |
| 0:44 | The battery clock | The buried cost is the battery. The standard requires three hundred and sixty five charge cycles, and guidance says charge daily. That is exactly twelve months. |
| 0:55 | What this is not | This page is not a costed proposal. No unit price, no headcount and no total appears anywhere on this site, because an invented number is worse than an absent one. |