Agenda:

Quasi Experimental Design: Basics

WSIPP drug court evaluation

Outcomes and Indicators for your projects

Next time: bring qualitative instrument for your project (focus group or interview protocol)

Quasi-experimental design: Goal: Pick a comparison group that looks like the intervention

group would have without the intervention

Can compare aggregate control and intervention groups

OR can match individual cases within intervention and control

– Can only use cases that HAVE a good match

– Can match to only 1 case or to more (e.g., 5 cases)

Can match on pre-intervention characteristics OR previous outcomes

Can use simple or multivariate techniques to match OR to control for differences when assess outcomes OR both

Impact here!

Quasi-experimental methods:

Propensity score matching Regression discontinuity design Instrumental Variables Multivariate regression of post-period

outcomes with controls Difference in difference regression Fixed Effects regression models

WSIPP drug court evaluation

What are the biggest challenges to picking a control group for people going through drug courts?

Worksheet on evaluation

Results

Results: Meta-analysis of 30 evaluations shows that drug

courts do decrease recidivism by about 13.3 percent (about 6 percentage points)

Six comparisons: – Similar counties or pre-drug court in previous period

– Regression, Propensity score, or risk score matching

Most drug courts in WA have reduced recidivism by similar levels to other studies; but not King Co.

Cost-benefit shows higher costs for drug courts, but they return $1.74 in benefits for each dollar of extra costs

Projects: What are your outcomes and indicators (can be for

process or impact)?

How do they capture the key impacts of the program?

How are the indicators appropriate and collectable?

In next memo you will need a chart with each research question, each outcome and indicator, and where the data will come from (see student examples)