CONTENTS

Table of Contents
Introduction

1. Descriptive Statistics in Evaluation
2. Subgroup Analysis
3. Variable - Are They Related?
4. Correlation
5. The t-Test of Difference Between Means

Supplements
Resources
Glossary

Wading Through the Data Swamp:
Program Evaluation 201

Research Designs

People use a number of different research designs to evaluate prevention programs. Although many work fine, some are not considered acceptable for getting a good estimate of a program's effect. Others may be difficult to implement for programs in schools or communities.

Here are the possible designs, along with their advantages and disadvantages:

• Posttest only.
• Pretest-posttest design without a comparison group.
• True experimental design (pretest-posttest design with a control group and random assignment of participants to either the program or the control group).
• Quasi-experimental design (pretest-posttest design with a comparison group but nonrandom assignment of participants to the program or control group).