A source of internal (causal) invalidity occurring when the characteristics of experimental and comparison group subjects differ in any way that influences the outcome is ______.

Question

Quizplus · Accepted Answer

Selection bias occurs when there is a difference in the characteristics of the groups being compared that affects the outcome. This can be due to non-random assignment to groups or other factors. Endogenous and exogenous changes refer to external validity concerns, and regression effect refers to the tendency for extreme scores to move closer to the mean over time. Therefore, selection bias is the best choice.

A Source of Internal (Causal) Invalidity Occurring When the Characteristics