Immediately after the intervention in an experimental study of the negative effects of smoking tobacco, the state tax on cigarettes increases the cost from $4 to $8 per pack. Which threat to internal validity does this pose?

Question

Quizplus · Accepted Answer

The increase in the state tax on cigarettes is an external event that occurred during the experiment, which could influence the study's outcomes independently of the intervention being tested. This is an example of a history threat to internal validity, as it involves specific events occurring between the first and second measurements that are not part of the manipulation.

Immediately After the Intervention in an Experimental Study of the Negative