Paper: Nagin (2013)

"Deterrence: A Review of the Evidence by a Criminologist for Economists", review paper in the Annual Review of Economics (2013).
== Summary ==
* Sections 3, 4, and 5: reviews evidence on the deterrent effect of imprisonment, police and capital punishment respectively.
* Section 6: summarizes knowledge of sanction risk perceptions.
* Section 7: identifies 4 areas for future research: (1), (2) measuring perceptions of sanction regimes, (3), and (4).
=== 1. Introduction ===
=== 2. Key Theoretical Ideas ===
Three key concepts in theory of deterrence: (1) certainty, (2) severity , and (3) immediacy/celerity of punishment.
=== 3. The Deterrent Effect of Imprisonment ===
* Two waves of studies on the deterrent effect of imprisonment: 
*# Gen 1 in the 1960-70s, cross-sectional analysis at the state level of the relation between crime rate and: (1) ratio of prison admissions/reported crimes (~certainty), and (2) median prison time (~severity). Drawbacks: (1) conflate deterrent and incapacitation effects, (2) crime rates and sanction levels are probably endogenous.
*# Gen 2: from 1990s, included longitudinal data. Did not separately estimate certainty and severity effects, but instead the relation between crime and imprisonment rates.
*# These are little informative about deterrence because: (1) conflate deterrent and incapacitation effects, (2) do not resolve endogenous determination of crime and imprisonment rates, and (3) suffer from the theoretical flaw that prison population is not a policy variable, but p and S are.
* Next, he briefly describes six studies that report convincing evidence of the deterrent effect of incarceration:
*# Weisburd et al. (2008) and Hawken & Kleinman (2009): study use of imprisonment to enforce fine payment and conditions of probation resp, and find substantial deterrent effects
*# Helland & Tabarrok (2007): analyze deterrent effect of California's third-strike provision, find moderate deterrence effect
*# Raphael & Ludwig (2003): find no deterrent effect of prison sentence increases for gun crimes
*# Lee & McCrary (2007) and Hjalmarsson (2009): find no deterrent effect of heightened threat of imprisonment from reaching adult court age
=== 4. The Deterrent Effect of Policing ===
Possible mechanisms on crime: presence, increased probability of apprehension, 
==== 4.1. Studies of Levels of Police Numbers and Resources ====
Number of studies using abrupt-change type methods where the regime change is exogenous to the crime rate. Mentions number of papers, they consistently find that more police officers on the street has a substantial deterrent effect on serious crime. These studies only look at the impact of a change, they don't speak to what the police does or what the mechanisms are.
==== 4.2. Police Deployment and Crime ====
Examine the crime-prevention effectiveness of alternative strategies for deploying police resources. Think: hot-spot policing, response times, problem-oriented policing—mechanisms unclear.
=== 5. The Deterrent Effect of Capital Punishment (93-95) ===
[SKIPPED]
=== 6. Sanction Risk Perceptions ===
[draws heavily on Apel (2013)].
Studies of sanction risk perceptions come in three forms: (1) surveys of knowledge of the sanction regime, (2) studies of the effect of apprehension on risk perceptions, and (3) scenario-based studies. 
==== 6.1. General Population Surveys ====
Apel (2013) identifies only two general public surveys on knowledge of statutory penalties for assault, rape, murder, and robberyThe four types that make up the FBI's crime index.: one conducted in the 1970s in Tucson, Arizona, and a study in the 1960s commissioned by the California Assembly.
==== 6.2. Studies of Situational Factors on Risk Perceptions ====
=== 7. Four Topics for Future Research ===
==== 7.1. Develop and Test an Integrated model of the Effects of the Threat and Experience of Punishment ====
==== 7.2. Measuring Perceptions of Sanction Regimes ====
==== 7.3. Developing and Testing a Theory of Criminal Opportunities ====
==== 7.4. Estimating the Deterrent Effect of Shorter Prison Sentences and Identification of High-Deterrence Policies ====
=== 8. Closing Comments ===