Answering the Why Question in Evaluation: The Causal-Model Approach

Theorists and researchers have urged that evaluation test the causal assumptions about why an intervention should work to achieve its goals. Though the terminology is different, these writers agree that the assumed pathway from program to ultimate outcome be made explicit and tested empirically. The causal-model approach, because it is geared toward providing evidence on why a program worked or failed, is advocated whenever time, money, and experience permit. After defining casual-model evaluation, an example from the crime prevention literature is used to contrast the approach with traditional evaluations. Benefits, limitations, and other issues are also discussed.