During an experiment on recidivism among juvenile offenders a researcher learned that 35 percent of the original participants moved out of state with their families. What type of threat to the internal validity of this experiment's results is this problem?

Question

Quizplus · Accepted Answer

The problem of participants moving out of state with their families is a threat to the internal validity of the experiment because it could introduce systematic differences between the remaining participants and those who left that are unrelated to the treatment being studied. This is known as mortality, which refers to the loss of participants from the study over time. Choices A and B refer to threats resulting from external events (e.g., changes in the social/political context, natural development of participants), while testing is a threat that arises from the effects of taking a pretest on subsequent measurements of the same construct.

During an Experiment on Recidivism Among Juvenile Offenders a Researcher