Professor James Byrne
Oct. 30 th 2014

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The Classic experiment has three components:
1. independent and dependent variables
2. pretesting and post-testing
3. experimental and control groups created via random assignment( variation on a theme: double blind experiments where neither the researcher or the subjects knows who is in experimental and control group)

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The Minneapolis Domestic Violence
Experiment: examined the short term impact of mandatory arrest( compared to counseling, and business as usual) in misdemeanor DV cases
The Kansas City Preventive Patrol
Experiment: impact of police on crime, fear, and arrests
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Random assignment to one of 3 conditions--control beats (normal level of preventive patrol);proactive( 2x level of preventive patrol); reactive beats( no preventive patrol)
The Newark Foot Patrol Experiment: impact of foot patrol on crime, fear, and arrests. Random assignment to foot patrol vs motorized patrol.

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1. Misapplication of treatment( e.g.
Minneapolis Experiment)
2. No difference in intervention between treatment and control groups( Newark Foot
Patrol)
3. External Validity: the experiment does not work in real world( boutique programs; research rich interventions)

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. History: outside events that could also explain findings( e.g. research in 70’s on impact of laws to reduce drunk driving)
2. Maturation: people change: example-age and binge drinking
3. Testing: subjects become sensitive to responses exampledrinking/drug use surveys( pre-post)
4. Instrumentation: changes in measurement over time ( example-hate crime)
5. Statistical Regression: selecting subjects with extreme scores on a dependent variable, such as chronic offenders.
6.Selection Bias: picking good risks example- drug courts, bail research
7.Experimental Mortality: Dallas Women in Policing Study; boot camp
8. Diffusion of Tx( targeted community policing) and Compensatory Tx(
Kansas City Ex
)

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1. Sample Size: Rand Study of ISP in 14 locations
2. Target group selection ( e.g. research study on certainty of incarceration by Weisburd; ISP refusals at two sites)
3. Lack of researcher control over random assignment: Minneapolis Experiment
4. After the fact random assignment: Project
Hope in Hawaii