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Published byEsther Townsend Modified over 8 years ago
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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. 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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1. 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 example- drinking/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
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