Which of the following is NOT true of selection effects?
A)Selection effects are a type of confound.
B)Selection effects can occur when experimenters allow participants to choose their own treatment group.
C)Selection effects are unimportant for interrogating internal validity.
D)Selection effects can occur when researchers assign one type of person to one treatment group and another type of person to another treatment group.

Question

Quizplus · Accepted Answer

Selection effects are important for interrogating internal validity because they can distort the relationship between the independent variable and the dependent variable. A selection effect occurs when participants who are different in meaningful ways are placed in different groups, making it difficult to determine whether differences between groups are due to the treatment or to pre-existing differences between the groups. A selection effect can arise from any procedure that results in non-random assignment of participants to groups, including self-selection or experimenter assignment based on participant characteristics.

Which of the Following Is NOT True of Selection Effects