loading page

Towards the Unification of External and Internal Validity: An Empirical Approach
  • Andrew Jaciw
Andrew Jaciw
Empirical Education Inc.

Corresponding Author:[email protected]

Author Profile


We evaluate the role of selection bias in causal generalization. We compare levels of bias in estimates of average causal impacts from experiments and from non-experiments. To demonstrate we use data from 79 sites in the multisite trial of Tennessee’s Student Teacher Achievement Ratio (STAR), and we use results obtained during a randomized experiment of the Alabama Math Science and Technology Initiaitve (AMSTI).