The most common threat to the internal validity of research designs is probably:
A)experimenter bias
B)confounds
C)participant expectancies
D)regression toward the mean

Question

Quizplus · Accepted Answer

Confounds are variables that are not being studied but affect the outcome variable, making it difficult to determine if the independent variable truly had an effect. Confounds can threaten the internal validity of a study by introducing alternative explanations for the results, leading to inaccurate conclusions. Experimenter bias, participant expectancies, and regression toward the mean can also threaten internal validity, but they are not as common as confounds.

The Most Common Threat to the Internal Validity of Research