Random assignment to conditions is used in true experiments to control which of the following threats to internal validity?
A) selection
B) testing
C) history
D) subject attrition

Question

Quizplus · Accepted Answer

Random assignment to conditions helps to control for selection bias, which refers to the possibility that there are differences between the groups in a study that could affect the outcome variable, and which cannot be attributed to the variables being manipulated or measured. By randomly assigning participants to groups, researchers can help ensure that any differences between the groups are due to chance, rather than some pre-existing characteristic of the participants. Testing, history, and subject attrition are examples of other threats to internal validity that may need to be controlled for in a study, but random assignment is specifically used to control for selection bias.

Random Assignment to Conditions Is Used in True Experiments to Control