Threats to internal validity

Question 1

History

Answer 1

The observed effects are caused by extraneous or historical events

Question 2

Maturation

Answer 2

natural changes or developments within the participants over time affect the results

Question 3

Testing

Answer 3

A participant’s results on the posttest are influenced by having taken a pretest (remembering the answer to a question)

Question 4

Instrumentation

Answer 4

When instrumentation changes, so the variable is measured differently

Question 5

Mortality

Answer 5

Subjects drop out of your study, so the groups change

Question 6

Regression

Answer 6

Subjects that score high on a pretest have a tendency to regress towards the mean on a post test, so score lower