INVESTIGATING THE STABILITY OF CO‐OFFENDING AND CO‐OFFENDERS AMONG A SAMPLE OF YOUTHFUL OFFENDERS*

• Date: 01 February 2008
• DOI: http://doi.org/10.1111/j.1745-9125.2008.00105.x
• Author: JEAN MARIE MCGLOIN,SARAH BACON,ALEX R. PIQUERO,CHRISTOPHER J. SULLIVAN
• Published date: 01 February 2008

\\server05\productn\C\CRY\46-1\CRY105.txt unknown Seq: 1 21-FEB-08 10:01

INVESTIGATING THE STABILITY OF CO-

OFFENDING AND CO-OFFENDERS

AMONG A SAMPLE OF YOUTHFUL

OFFENDERS*

JEAN MARIE MCGLOIN

Department of Criminology and Criminal Justice

University of Maryland

CHRISTOPHER J. SULLIVAN

Department of Criminology

University of South Florida

ALEX R. PIQUERO

John Jay College of Criminal Justice &

City University of New York Graduate Center

SARAH BACON

College of Criminology and Criminal Justice

Florida State University

KEYWORDS: co-offending, juvenile offending, criminal careers

Scholars have long argued that delinquency is a group phenomenon.

Even so, minimal research exists on the nature, structure, and process

of co-offending. This investigation focuses on a particular void, namely

the stability of 1) co-offending and 2) co-offender selection over time,

for which divergent theoretical expectations currently exist that bear on

issues central to general and developmental/life-course theories of

crime. By relying on individual-level, longitudinal data for a sample of

juvenile offenders from Philadelphia, we find that distinct trajectories

* The authors would like to thank Matthew DeLisi and David Weisburd for their

comments on earlier drafts of this manuscript as well as Brian Johnson, Laura

Dugan, Hanno Petras, and Lee Ann Slocum for helpful suggestions and

comments on the analysis. We would also like to dedicate this manuscript to the

memory of Joan McCord, who, with Kevin Conway, had the foresight to collect

the original data used in this article. Direct correspondence to Jean Marie

McGloin, Department of Criminology and Criminal Justice, University of

Maryland, 2220L LeFrak Hall, College Park, MD 20742 (e-mail:

jmcgloin@crim.umd.edu).

CRIMINOLOGY V

OLUME

46 N

UMBER

1 2008 155

\\server05\productn\C\CRY\46-1\CRY105.txt unknown Seq: 2 21-FEB-08 10:01

156 MCGLOIN, SULLIVAN, PIQUERO & BACON

of co-offending exist over the course of the juvenile criminal career.

This inquiry also develops an individualized measure of co-offender

stability, which reveals that delinquents generally tend not to “reuse”

co-offenders, although frequent offenders show a greater propensity to

do so. The discussion considers the theoretical and policy implications

of these findings as well as provides some avenues for future research.

In 1912, Breckenridge and Abbott stated that, “there is scarcely a type

of delinquent boy who is not associated with others in his wrongdoing”

(1912: 35). Nearly one century later, this observation is a criminological

axiom. Indeed, McCord and Conway (2002) argued recently that co-

offending is an inherent part of delinquency, as evidenced by some of the

field’s seminal works (see Cloward and Ohlin, 1960; Cohen, 1955; Shaw

and McKay, 1942; Short and Strodtbeck, 1965; Sutherland, 1947). As Reiss

(1986) demonstrated, the group nature of offending becomes even more

apparent when considering the individual, rather than the incident, as the

unit of analysis. For example, his incident-level analysis reveals that in

1984, approximately half of robbery victimizations in the United States

were committed by two or more people. Individual-level analysis, how-

ever, shows that nearly three quarters of robbers offended with at least

one other individual. The pervasiveness of co-offending seems to persist

across both time and location, as well as when using official records and

self-reports (Warr, 2002). For such reasons, Warr (1996) has suggested that

the group nature of delinquency is an essential, not an incidental,

characteristic.

Existing aggregate analyses suggest that co-offending is simply a “fact”

of crime, but sufficient variability exists in the nature, process, and struc-

ture of co-offending over time and across individuals to warrant closer

inspection (Piquero, Farrington, and Blumstein, 2007; Sarnecki, 2001).

Even so, this essential characteristic has received minimal theoretical and

empirical attention (McCord and Conway, 2002), which is partly because

of extant data constraints. Despite the fact that co-offending is an impor-

tant dimension of the criminal career (Piquero, Farrington, and Blumstein,

2003; Reiss, 1986), it has yet to be integrated into discussions about the

continuity/change of offending over the life course. Although research has

advanced our understanding of the role of deviant peers—the pool from

which offenders typically select co-offenders over the criminal career

(Warr, 2002)—the extent to which co-offending sheds insight on the onset,

persistence, frequency, variety, and desistence of offending, or vice versa,

remains largely unknown. This is unfortunate because the implication of

empirical patterns for theory, policy, and crime estimates should sensitize

us to the importance of individualized empirical inquiries.

\\server05\productn\C\CRY\46-1\CRY105.txt unknown Seq: 3 21-FEB-08 10:01

STABILITY OF CO-OFFENDING AND CO-OFFENDERS 157

To be sure, investigations of co-offending do exist (see Carrington, 2002;

Conway and McCord, 2002; McCord and Conway, 2005; Pettersson, 2003;

Reiss, 1986, 1988; Reiss and Farrington, 1991; Sarnecki, 2001, 2004; Suzuki

et al., 1994), but much of this literature offers aggregate statements about

cross-sectional patterns or broad assessments of change across long time

periods. In contrast, approaches that use individualized methods may shed

unique insight on offending patterns over the criminal career (Maltz and

Mullany, 2000; Nagin, 2005; Sullivan et al., 2006). For example, one rela-

tively consistent finding about co-offending is that it tends to decline with

age. This trend may be general, but it may also mask patterns of stability

and/or varying pathways that aggregate to a negative slope. Understanding

whether variations exist and are patterned in any systematic manner can

provide additional fodder for discussion as theorists and policy makers

wrestle with the question of criminal career pathways.

With such a focus on continuity and change in mind, this inquiry centers

on the stability of co-offending (i.e., the stability of the tendency to co-

offend) and on the stability of co-offenders (i.e., the tendency to “reuse”

co-offenders) over time. To shed insight on these issues, this study applies

a variety of innovative analytic techniques, which include trajectory analy-

sis and a derived co-offender stability measure, to longitudinal data from a

sample of youthful offenders from Philadelphia.

CO-OFFENDING OVER THE LIFE COURSE

Recently, Weerman (2003: 22) identified eight “facts” about co-offend-

ing. Of these facts, three underscore the importance of a life-course

approach. First, he states that offenders have varying proclivities for co-

offending. On this point, Warr (1996: 22) found strong correlations across

offenses that suggested offenders “commonly exhibit a style of offending

(i.e., group or loner) for offenses of any given type.” In contrast, Reiss

(1988: 123) states that: “a large proportion of offenders exhibit neither

exclusively lone nor exclusively co-offending. Most offender histories are

characterized by a mix of offending alone and with accomplices” (see also

Conway and McCord, 2002). In the end, offenders’ criminal careers typi-

cally illustrate a combination of solo and co-offending, although individual

preferences usually emerge (Hindelang, 1971, 1976). Second, co-offending

has a negative relationship with age. Empirical evidence suggests that the

probability of co-offending declines over the criminal career (see Car-

rington, 2002; Conway and McCord, 2002; McCord and Conway, 2005;

Piquero, Farrington, and Blumstein, 2007; Reiss and Farrington, 1991).

This aggregate relationship may reflect the movement of individuals away

from co-offending toward solo offending as they age, or it may reflect the

selective desistence of the individuals who are most inclined toward co-