The following quotations* are from Deterrence in the Twenty-first Century by Daniel Nagin:
“Certainty of apprehension and not the severity of the legal consequence ensuing from apprehension is the more effective deterrent.” In other words, the certainty of getting caught is a greater crime deterrent than severity of punishment.
“Non-offenders and novice offenders have higher sanction risk perceptions than experienced offenders.” In other words, less experienced offenders are more sensitive to the risk of getting caught.
“Risk perceptions are affected by an individual’s own experience with success or failure at averting apprehension.” In other words, the better you have been at avoiding apprehension, the less you worry about it.
“Deterrables are individuals …who are attentive to sanctions threats. For such individuals the issue is whether the net benefit of successful commission [of the criminal act] exceeds the potential costs attending failure.” In other words, some offenders or would-be offenders take a ‘rational actor’ approach to committing crimes, weighing potential costs and benefits, and altering their behavior accordingly.
“The incorrigible group is also composed of individuals for whom crime is profitable but who for whatever reason are not attentive to sanction threats.” I would guess these individuals are impulsive, supremely self-confident, macho-brave, and/or “can do” optimists.
“There is substantial evidence that increasing the visibility of the police by hiring more officers and allocating existing officers in ways that materially heighten the perceived risk of apprehension can deter crime.” In other words, the mere presence of police deters crime, because it increases the perceived risk of getting caught.
“From a crime control perspective, the apprehension agent function protects public safety by capturing and incapacitating sometimes dangerous and repetitive offenders. However, as yet there is no evidence that the apprehension agent role results in a material deterrent effect.” For example, the clearance rates for violent and property crimes have been stable since the 1970s, but US crime rates have varied considerably over the same period. (Braga, 2021). Since most crimes are cleared by arrests, this would seem to indicate that higher arrest rates would not result in lower crime rates.
“By contrast, the evidence on police presence suggests that in their sentinel [aka “guardian”] role police can have a very large deterrent effect.” That is, arresting people deters crime less than maintaining a police presence in an area.
“The certainty effect stems primarily from police functioning in their official guardian role rather than in their apprehension agent role…[For instance], an idling police car outside a liquor store greatly reduces the chance, probably to zero, that the store can be successfully robbed.”
“Protection may also be provided by [other] guardians such as security guards, vigilant employees, or onlookers who are willing to intervene.” The certainty risk here may the immediate risk of interference and unwanted attention, which in turn increases the risk of apprehension.
Ok, so fear of getting caught deters crime more than fear of the legal consequences after getting caught. That makes sense, given that the former is a more immediate concern than the latter. But then, if getting caught were never followed by serious consequences, it would cease being a threat. Consequences still matter.
Also, the purpose of arresting and incapacitating offenders is not just to deter crime but to to protect the public from specific individuals, especially dangerous and repeat offenders. So of course, some offenders need to be locked away for a time, hopefully not too long and combined with serious rehabilitation and reentry assistance.
Still, point taken: it’s better to avert crime in the first place than to intervene after the event.
Next: Why clearance rates still matter
—
* I’ve altered the capitalization and punctuation on several quotes, many of which were part of longer sentences.
References:
Braga, Anthony A. Improving Police Clearance Rates of Shootings: A Review of the Evidence, Manhattan Institute, July 2021.
Nagin, Daniel S. (2013). Deterrence in the Twenty-first Century, Crime and Justice, 42(1), 199–263.