Nonexperimental Lalonde Data: Estimates of Average Treatment Effects (standard errors in parentheses)
| Covariate | Full Sample | Trimmed Sample | ||||
|---|---|---|---|---|---|---|
| 1 Block | Match | 1 Block | 2 Blocks | 4 Blocks | Match | |
| Number | −8.50 (0.58) | 1.72 (0.90) | 1.72 (0.74) | 1.81 (0.75) | 1.79 (0.76) | 1.98 (0.85) |
| Few | 0.69 (0.59) | 1.73 (0.90) | 1.81 (0.73) | 1.80 (0.73) | 2.10 (0.75) | 1.98 (0.85) |
| All | 1.07 (0.55) | 1.81 (0.90) | 1.97 (0.66) | 1.90 (0.67) | 1.93 (0.70) | 2.06 (0.85) |