Another Piece of the Puzzle: The Importance of Officer Characteristics and Group Processes in Understanding Post-stop Outcomes

• Published date: 01 August 2019
• Author: Rob Tillyer,Michael Smith,Caleb D. Lloyd
• Date: 01 August 2019
• DOI: 10.1177/0022427819843962
• Subject Matter: Articles

Article

Another Piece

of the Puzzle: The

Importance of Officer

Characteristics

and Group Processes

in Understanding

Post-stop Outcomes

Rob Tillyer

1

, Michael Smith

1

, and Caleb D. Lloyd

2

Abstract

Objectives: Investigate the potential relationship between officer character-

istics and poststop outcomes during police–citizen encounters. Methods:

Data on police-initiated contacts were drawn from a large, racially/ethni-

cally mixed urban environment. Cross-classified, multilevel models were

estimated to identify correlates of five poststop outcomes. Results: Officer

gender, race/ethnicity, and length of service exerted a direct and/or mod-

erating effect on the likelihood of a traffic citation, criminal citation, and a

search. Conclusions: Officer characteristics are a key, yet understudied, com-

ponent to understanding the complexities of police officer decision-making

1

Department of Criminal Justice, The University of Texas at San Antonio, San Antonio,

TX, USA

2

Centre for Forensic Behavioural Science, Swinburne University of Technology, Alphington,

Victoria, Australia

Corresponding Author:

Rob Tillyer, Department of Criminal Justice, The University of Texas at San Antonio, 501 W.

Cesar E. Chavez Blvd., San Antonio, TX 78207, USA.

Email: rob.tillyer@utsa.edu

Journal of Research in Crime and

Delinquency

2019, Vol. 56(5) 736-779

ªThe Author(s) 2019

Article reuse guidelines:

sagepub.com/journals-permissions

DOI: 10.1177/0022427819843962

journals.sagepub.com/home/jrc

in police–citizen encounters. The results indicate a noticeable component

of the variation in poststop outcomes rests at the off icer level thereby

substantiating the continued exploration of these relationships. Moreover,

the moderating effect of officer characteristics on the relationship between

minority citizens and poststop outcomes presents new potential directions

for expanding the social conditioning model and offers evidence regarding

the in-group versus out-group perspectives within the context of police–

citizen interactions. Limitations include omitted variable bias and inexact

measurement of some variables.

Keywords

police officer decision-making, poststop outcomes, intergroup processes,

cross-classified, multilevel modeling

Police–citizen encounters continue to generate attention among minority

groups, academics, the media, and broader society. Focus on this issue is

fueled, at least partially, by recent high-profile events across the country,

perhaps most notably in Ferguson, Missouri, although numerous other

examples exist. Interest in these incidents revolves around the treatment

of minority citizens by police, not only during initial contact but also in the

encounter’s resolution. Empirical evidence on officer-initiated police–citi-

zen encounters indicates a pattern of disproportionate treatment of minority

citizens in an officer’s decision to search a citizen or a vehicle (Engel and

Johnson 2006; Rosenfeld, Rojek, and Decker 2012), initiate an arrest

(Kochel, Wilson, and Mastrofski 2011), and/or issue a citation/ticket (Engel

and Calnon 2004).

1

Other citizen characteristics (Tillyer 2014), situational

aspects of the encounter (Rojek, Ro senfeld, and Decker 2012), and the

broader environmental context (Novak and Chamlin 2012) also exert an

influence on these poststop outcomes.

While acknowledging the contribution of these studies, prior research

has primarily examined potential correlates using models that do not first

establish the relative degree of importancethatshouldbeplacedoneach

of these domains. This includes studies that have sought to identify and

specify the potential influence of officer characteristics on poststop out-

comes. Stops occur in a dynamic and uncertain environment where many

factors partially determine poststop outcomes, including, for example,

recorded information about the citizen, the context of the stop, and the

officer’s characteristic approach to handling interactions with citizens.

Tillyer et al. 737

Thus, initially, it is important to estimate the degree to which poststop

outcomes may vary due to officer decision-making while simultaneously

accounting for other factors. If differences in poststop outcomes are sub-

stantially related to officers, this has implications, given that law enforce-

ment agencies cannot control most factors at play within police–citizen

encounters but can and should attend to the degree of consistency across

officer decision-making. More broadly, appropriately modeling the

degree of variance in legal decision-making that is associated with the

decision-maker himself or herself is highly relevant to many legal con-

texts; even well-informed judges, jury members, parole officers, and

expert witnesses, for example, make decisions within a social and rela-

tional context that is not immune to extralegal factors, variation, potential

bias, or error. In this study, we argue that it is necessary to first establish

the degree to which officer characteristics are relevant and related to

poststop outcomes. If relevant, it is then critical to begin to understand

the components of officer decision-making processes, develop theoretical

explanations, and create relevant policy decisions.

Critical initial work has begun in this area (e.g., Alpert, Dunham, and

Smith 2007; Baumgartner et al. 2017; Close and Mason 2006, 2007; Rojek

et al. 2012; Tillyer, Klahm, and Engel 2012); however, much is still not

understood about the empirical influence of officer characteristics on

poststop outcomes. For example, to the extent that officer characteristics

have been examined, the results are inconsistent and somewhat c ontra-

dictory. Additionally, theoretical explanations for why officers may vary

in their treatment of citizens have not been fully developed. This is an

underexamined and critical area, given that officers represent half of a

police–citizen encounter and possess a significant portion of the decision-

making power in these events. Disentangling the complexities of police–

citizen encounters requires empirical clarity regarding the relationship

between officer characteristics and poststop outcomes, and we extend this

effort by also presenting a theoretical mechanism that offers avenues for

interpreting the results.

The current study uses data from a large, racially/ethnically diverse city

to test for direct effects between officer characteristics (e.g., race/ethnicity,

gender, age, length of service) and poststop outcomes (i.e., citations, arrests,

and searches). Our investigation of these relationships aims to accomplish

five specific goals. First, we extend our knowledge of these relationships by

bringing new empirical data to bear on the existing empirical inconsisten-

cies. In particular, these data catalogue police–citizen encounters within a

diverse racial/ethnic environment that reflects the changing demographics

738 Journal of Research in Crime and Delinquency 56(5)