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

Threats to External Validity

People

This threat relates to characteristics of participants. For example, participants in your study may have healthier outlooks on drug use than most other children their age.

Places

This threat relates to the venue of the program. For example, the area your program takes place in may be within walking distance of many drug prevention resources.

Times

This threat relates to the timing of the program. For example, your program may take place at the same time that another huge drug prevention campaign is launched.