When a researcher asks the question, "Have subjects been pre-selected so as to represent the extremes on the variable of interest?" she is concerned with which one of the following potential threats to internal validity?
A) testing effect
B) maturation
C) subject selection
D) regression effect

Question

Quizplus · Accepted Answer

The regression effect, also known as regression to the mean, occurs when subjects are selected based on extreme scores and their scores tend to move towards the average on subsequent testing, potentially affecting the study's internal validity.

When a Researcher Asks the Question, "Have Subjects Been Pre-Selected