Hot vs. Cold Cases: Examining Time to Clearance for Homicides Using NIBRS Data

• DOI: 10.3818/JRP.9.2.2007.87
• Published date: 01 December 2007
• Date: 01 December 2007
• Author: Lynn A. Addington
• Subject Matter: Article

HOT VS. COLD CASES • 87

*

Hot vs. Cold Cases:

  Examining Time to Clearance for

 Homicides Using NIBRS Data

Lynn A. Addington

American University

* Abstract

Very little attention has been devoted to studying factors associated with how

quickly murders are cleared. This dearth of knowledge is mainly due to a lack

of available data, especially at the national level. Currently the Uniform Crime

Reporting Program is undergoing a large-scale conversion from its traditional

summary system form of data collection to the National Incident-Based Reporting

System (NIBRS). One benet of NIBRS is that it enables law enforcement agencies

to report incident-level clearance information, including the incident and clearance

dates. The present study utilizes NIBRS data to compare characteristics of homicides

that are cleared quickly with those cleared over a longer period of time and those

that are not cleared. Findings from this exploratory study conrm the conventional

belief that murders are cleared quickly if at all, as a large drop in the percentage

of cleared cases is observed one week after a murder occurs. The present research

also suggests that incident characteristics play a dynamic role in predicting not only

whether a murder is cleared, but how quickly. These ndings provide new insights

for studying clearance and suggest policy implications.

An earlier version of this paper was presented at the Bureau of Justice Statistics/Justice

Research and Statistics Association 2006 National Conference, Denver, Colorado, October

13, 2006. My thanks to the editors and anonymous reviewers for their helpful suggestions.

JUSTICE RESEARCH AND POLICY, Vol. 9, No. 2, 2007

© 2007 Justice Research and Statistics Association

88 • JUSTICE RESEARCH AND POLICY

HOT VS. COLD CASES • 89

Murder clearance rates are important criminal justice measures for criminolo-

gists, practitioners, and the general public.1 Academic researchers use clearances

to develop theories about police behavior. For police departments and policy-

makers, clearance rates can have more practical and immediate implications,

as they are a readily available—if limited and problematic (Riedel & Jarvis,

1999)—measure of police performance. Citizens also take note of clearance

rates, especially during spikes in murder rates or in the wake of highly publi-

cized, unsolved murder cases. Conventional wisdom suggests that murders tend

to be solved quickly if they are solved at all (e.g., Simon, 1991). Little research

attention has been devoted to testing these assumptions and no national studies

exist concerning time to clearance.

Relatively little is known about murder clearances overall. Only a handful

of studies have examined factors related to these clearances and even fewer

have examined time to clearance. One reason for this dearth of knowledge is a

lack of available data. Until fairly recently, homicide researchers were limited

to selecting either aggregate-level clearance data from the Uniform Crime Re-

porting Program’s (UCR) summary system or incident-level data with no clear-

ance information from the UCR’s Supplementary Homicide Report (SHR).

Neither of these sources provides information regarding time to clearance.

Currently the UCR is in the process of a substantial conversion from its tradi-

tional summary system form of data collection to the National Incident-Based

Reporting System (NIBRS). Unlike the summary system and its SHR, NIBRS

provides incident-level details including incident and clearance dates for mur-

ders as well as for over 40 other crimes (Federal Bureau of Investigation [FBI],

1992). Although NIBRS provides a new and important source of clearance

information, researchers have largely ignored these data (but see Addington,

2005, 2006; Chilton & Jarvis, 1999). This omission is unfortunate, since one

of the goals in redesigning the UCR program was to improve clearance infor-

mation in order to allow for the exploration of these statistics (Poggio, Ken-

nedy, Chaiken, & Carlson, 1985). The present study seeks to utilize NIBRS

data to examine time to clearance, in particular the factors associated with

murders that are cleared quickly as compared to those cleared over a longer

period of time or not cleared at all.

1 This article purposefully uses the term “clearance” rather than the more specic

term “arrest.” This terminology parallels the Federal Bureau of Investigation’s (FBI)

practice of considering a crime cleared or “solved” for crime reporting purposes if there

has been either an arrest or activity constituting clearance by exceptional means (FBI,

2004). Clearance by exceptional means refers to situations in which a suspect has been

identied, but circumstances beyond the agency’s control prevent an arrest, such as the

death of the suspect.