Table 2.
Comparison of the Aspects of Evaluating Social Policies that are Covered by the Neyman-Rubin Approach and the Structural Approach
| Neyman-Rubin Frame- work |
Structural Framework | |
|---|---|---|
| Counterfactuals for objective outcomes (Y0, Y1) | Yes | Yes |
| Agent valuations of subjective outcomes (ID) | No (choice-mechanism implicit) |
Yes |
| Models for the causes of potential outcomes | No | Yes |
| Ex ante versus ex post counterfactuals | No | Yes |
| Treatment assignment rules that recognize the vol- untary nature of participation |
No | Yes |
| Social interactions, general equilibrium effects and contagion |
No (assumed away) | Yes (modeled) |
| Internal validity (problem P1) | Yes | Yes |
| External validity (problem P2) | No | Yes |
| Forecasting effects of new policies (problem P3) | No | Yes |
| Distributional treatment effects | Noa | Yes (for the general case) |
| Analyze relationship between outcomes and choice equations |
No (implicit) | Yes (explicit) |
a
An exception is the special case of common ranks of individuals across counterfactual states: “rank invariance.” See the discussion in Abbring and Heckman (2007).