1. Quantitative Research

2. Experimental Research Categories
Randomized Experimental
Use of comparison groups
Random assignments to groups
Quasi-experimental
“Manipulates treatments” but doesn’t use randomly assigned treatment groups
Used when randomization of groups is impossible
Typically has a pretest and posttest
Pre-experimental
No comparison group
No pretest/weak design

3. Internal Validity
Indicates the extent to which the study is free of extraneous or confounding variables or factors that might account for results.
i.e., could effects be due to enthusiastic teacher rather than the program under investigation?

4. Threats to Internal Validity (p.61)
Extraneous events
Selection
Maturation
Subject attrition
Pretesting (testing)
Statistical regression
Diffusion of treatment
Experimenter effects
Treatment fidelity
Subject effects
Instrumentation

5. Criteria for Evaluating
Is purpose clear? Significant?
Review of Lit—Current? Organized?
Is hypothesis/question(s) clearly stated?
Is method of sampling clear?
What was manipulated as independent variable(s)
Are procedures for collecting data described fully?
Are there any threats to internal validity?
Do conclusions/interpretations follow logically from the results?
Are limitations indicated?
Is experiment so contrived and artificial that the findings have little generalizability?

6. Class Activity
In your content groups, answer the questions (3, 4, 7 & 9) on pp
Fill in the Credibility Scorecard on p. 73