More cops, fewer prisoners?

• Author: Aaron Chalfin,Jacob Kaplan
• DOI: http://doi.org/10.1111/1745-9133.12424
• Date: 01 February 2019
• Published date: 01 February 2019

DOI: 10.1111/1745-9133.12424

RESEARCH ARTICLE

MORE COPS, FEWER PRISONERS?

More cops, fewer prisoners?

Jacob Kaplan Aaron Chalfin

University of Pennsylvania

Correspondence

JacobKaplan, 483 McNeil Building,

Universityof Pennsylvania, 3718 Locust

Walk,Philadelphia, PA 19104.

Email:jacobkap@sas.upenn.edu

Research Summary: The results reported in a large

amount of the criminology literature reveal that hiring

police officers leads to reductions in crime and that invest-

ments in police are an efficient means of crime control com-

pared with investments in prisons. One concern, however,

is that because police officers make arrests in the course of

their duties, police hiring, albeit efficient, is an inevitable

driver of “mass incarceration.” In this article, we consider

the dynamics through which police hiring affects down-

stream incarceration rates.

Policy Implications: Using state-level panel data as well

county-level data from California, we uncover novel evi-

dence in favor of a potentially unexpected and yet entirely

intuitive result: that investments in law enforcement are

unlikely to increase state prison populations markedly and

may even lead to a modest decrease in the number of state

prisoners. As such, investments in police may, in fact, yield

a “double dividend” to society by reducing incarceration

ratesaswellascrimerates.

KEYWORDS

crime, incarceration rates, police, prison

There are two primary mechanisms through which criminal justice policy inputs like police and

prisons can reduce crime: deterrence and incapacitation. Deterrence represents a behavioral response

of crime to a given crime control strategy and is based on the idea that a rational offender will reduce

the amount of crime he or she supplies when the price of crime (which is, in turn, a function of the

certainty of apprehension and the severity of the expected sanction) increases. This conception of

deterrence is a core idea in Becker's (1968) seminal contribution to the economics of crime and in

Cornish and Clarke's (2013) The Reasoning Criminal and can be found in early treatises on the subject

by Beccaria (1785) and Bentham (1793) and later extensions by Ehrlich (1973), Shavell (1991), and

McCrary (2010) among others.1Incapacitation, on the other hand, represents a mechanical response of

Criminology & Public Policy. 2019;18:171–200. wileyonlinelibrary.com/journal/capp © 2019 American Society of Criminology 171

172 KAPLAN AND CHALFIN

crime to police and is premised on the idea that by arresting and subsequently incarcerating offenders,

some number of crimes will be abated—or incapacitated—away.2

Deterrence, it has been noted, is inexpensive relative to incapacitation (Nagin, 2013). Even though

preventing crimes via incapacitation requires that municipal and state governments finance the consid-

erable costs of arresting, adjudicating, and confining offenders, deterrence has far fewercosts. Accord-

ingly, the cost-effectiveness of a given crime control strategy will depend on the relative mixture of

deterrence and incapacitation effects that the strategy generates. Critically, if deterrence effects are

sufficiently large, it is possible for a crime control strategy to reduce both crime and incarceration,

allowing society to achieve a “double dividend” in which two costly outcomes—crime and resources

allocated to crime control—are simultaneously minimized (Durlauf & Nagin, 2011).

A critical task then for scholars of criminal justice policy is to generate evidence not only around

the efficacy of a given crime control strategy but also its cost-effectiveness in reducing crime. Natu-

rally, one of the principal crime control strategies employed bygovernments around the world involves

public investments in lawenforcement. In a large amount of published literature, scholars have consid-

ered the responsiveness of crime to the presence and availability of police and have found that police

resources have a modest but, in general,impor tant impact on crime.3With respect to police manpower,

prevailing estimates indicate that a 10% increase in police hiring will reduce violent crimes by between

4% and 10% and property crimes by between 2% and 5% (Cook, Kapustin, Ludwig, & Miller, 2017;

DeAngelo & Hansen, 2014; Evans & Owens, 2007; Levitt, 2002; Marvell & Moody, 1996; McCrary,

2002; Weisburst, 2016; Worrall & Kovandzic, 2010) and that, given these estimates, the benefits of

hiring police officers likely exceeds the cost of doing so (Chalfin & McCrary, 2017a).4

The extent to which police are a cost-effective crime control strategy is less certain as it is diffi-

cult to disentangle deterrence empirically from incapacitation effects (Kessler & Levitt, 1999; Owens,

2013; Webster, Doob, & Zimring, 2006). In summarizing the literature, however, scholars have noted

that there is considerable evidence—both theoretical and empirical—to suggest that investments in

law enforcement are an efficient means of controlling crime when compared with investments in cor-

rections (Chalfin & McCrary, 2017b; Durlauf & Nagin, 2011; Nagin, 2013). Empirically, this is seen

in recent estimates of the elasticity of crime with respect to the prison population, which is, at most,

approximately –0.1 to –0.2, considerablysmaller in magnitude t han the crime–police elasticity (Cullen,

Jonson, & Nagin, 2011; Durlauf & Nagin, 2011; Johnson & Raphael, 2012; Liedka, Piehl, & Useem,

2006; Nagin, 2013; Raphael, Lofstrom, & Martin, 2017). With respect to theory, beginning with Ben-

tham (1793), scholars have noted that because apprehension and subsequent incarceration are both

uncertain and indeed improbable for most crimes, to the extent that offenders are myopic, offending

will be more sensitive to the certainty of punishment that is experienced in the present rather than to

the severity of punishment that is experienced in the future (Durlauf & Nagin, 2011; Lee & McCrary,

2017; Nagin, 2013; Paternoster, 2010). Given the modest relationship between crime and state prison

populations as well as the concern that the experience of prison could itself be criminogenic, a con-

sensus has developed among criminal justice policy scholars that social planners could maximize the

effectiveness of public safety resources byreallocating away from investments in incarceration toward

investments in law enforcement (Chalfin & McCrary, 2017b; Durlauf & Nagin, 2011).

In recent years, as crime has declined from its national peak in the early 1990s, policy makers and

citizens alike have turned their attention to the collateral harms of incarceration—costs that fall dispro-

portionately on low-income, racially segregated neighborhoods from which the incarcerated popula-

tion is predominately drawn (Aizer & Doyle, 2015; Clear, 2009; Foster & Hagan, 2009; Genty, 2002;

Hagan & Dinovitzer, 1999; Mueller-Smith, 2015; Turanovic, Rodriguez, & Pratt, 2012). As attention

has turned to the social harms of “mass incarceration,” it has been suggested that spending on both

prisons and police has been excessive (Tonry, 2011). After all, the story goes, even if the police affect