Experiments and Quasi-Experiments

I. True Experiments

A. Characteristics of True Experiments

B. Types of True Experiments

1. Classical Experimental Design

2. The Posttest-only Control Group Design

II. Quasi-Experiments

A. Characteristics of Quasi-Experiments

B. Types of Quasi-Experiments

1. Time Series

2. The Nonequivalent Control Group Design

3. Static Group Comparison

III. Experimental Validity

A. Internal Validity

1. Definition

2. Threats to Internal Validity

B. External Validity

1. Definition

2. Threats to External Validity

C. Comparing True and Quasi-Experiments

IV. Examples of Experiments