Linking Prediction and Prevention

• Author: Greg Ridgeway
• Published date: 01 August 2013
• Date: 01 August 2013
• DOI: http://doi.org/10.1111/1745-9133.12057

POLICY ESSAY

FORECASTING CRIMINAL BEHAVIOR

Linking Prediction and Prevention

Greg Ridgeway

National Institute of Justice

First, I want to congratulate Berk and Bleich (2013, this issue) for their article

that advances the use of modern statistical prediction methodology in criminal jus-

tice. Opportunities abound in the criminal justice system to use statistical prediction

methods to improve decision making. Successdepends on the quality of the prediction mod-

els, the quality of the prevention efforts, and the quality of the link between prediction and

prevention. This policy essay will focus on these three components, which are essential to

the effective blend of humans and machines in making criminal justice decisions.

Prediction Models

The science of prediction continues to evolve. This evolution includes the development of

new statistical theory and methods, instantiation of those methods in software, improve-

ments in data collection, and evaluation of these new data and methods on practical criminal

justice issues.

Berk and Bleich (2013) cover numerous foundational issues that should be well un-

derstood by quantitative criminal justice scholars. These issues include recognizing the

distinction between prediction and explanation, the need for validating prediction models

in terms of out-of-sample predictive performance, and that not all prediction errors carry

the same cost. In addition, Berk and Bleich note that prediction methods have advanced

greatly. No longer should traditional regression be the only prediction tool in the criminal

justice analyst’s toolbox. Tools such as random forests and boosting are readily (and freely)

available thanks to open-source implementations, including my implementation of general-

ized boosted models that now has a large user and developer community (Ridgeway, 2013).

The current criminal justice literature has sufficient examples of the use of these tools so

that no mystery should remain around them.

. The findings and conclusions reported in this article are those of the author and do not necessarily

represent the official position or policies of the U.S. Department of Justice. Direct correspondence to

Greg Ridgeway, National Institute of Justice, 810 Seventh Street NW, Washington, DC 20531 (e-mail:

greg.ridgeway@usdoj.gov).

DOI:10.1111/1745-9133.12057 Published 2013. This article is a U.S. Government

work and is in the public domain in the USA

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Criminology & Public Policy rVolume 12 rIssue 3