During an experiment to evaluate the effectiveness of a new public relations program used by a police department to improve its relationship with the community, an errant police officer shoots and kills an unarmed teenager. What type of threat to the internal validity of this experiment's results is this problem?

Question

Quizplus · Accepted Answer

The shooting of an unarmed teenager is an external event that is unrelated to the experiment, but it can affect the results of the experiment. This is a history threat because it is a specific event that occurs during the experiment that could influence the results.

During an Experiment to Evaluate the Effectiveness of a New