Placebo Effect: Estimates of Average Treatment Effect on the Treated for Lake Recreation
| Participation in 2003 I | Difference in Participation II | Total Trips in 2003 III | Difference in Total Trips IV | |
|---|---|---|---|---|
| Treatment Group 1: Unemployed, Part-time, and Retired | ||||
| Nearest neighbor with replacement | 0.019 (0.072) | 0.007 (0.075) | –0.069 (1.223) | 0.226 (0.946) |
| Nearest five neighbors with replacement | 0.035 (0.057) | –0.024 (0.056) | 0.748 (1.006) | 0.045 (0.789) |
| Radius matching (caliper = 0.5 ×SD) | 0.011 (0.047) | –0.031 (0.052) | –0.134 (0.713) | 0.252 (0.676) |
| Kernel matching | 0.019 (0.050) | –0.035 (0.058) | 0.121 (0.750) | 0.224 (0.690) |
| Treatment Group 2: Unemployed and Part-time | ||||
| Nearest neighbor with replacement | 0.108 (0.094) | –0.075 (0.100) | –0.564 (1.545) | 0.797 (1.225) |
| Nearest five neighbors with replacement | 0.074 (0.073) | –0.044 (0.073) | 0.125(1.150) | 0.361 (0.659) |
| Radius matching (caliper = 0.5 ×SD) | 0.082 (0.065) | –0.072 (0.071) | 0.48 (0.741) | –0.491 (0.647) |
| Kernel matching | 0.077 (0.061) | –0.074 (0.068) | 0.295 (0.774) | –0.532 (0.637) |
| Treatment Group 3: Retired | ||||
| Nearest neighbor with replacement | –0.039 (0.080) | 0.005 (0.075) | –0.228 (1.718) | 0.745 (1.305) |
| Nearest five neighbors with replacement | –0.011 (0.066) | 0.017 (0.068) | 0.222 (1.350) | 0.277 (1.135) |
| Radius matching (caliper = 0.5 ×SD) | –0.051 (0.060) | 0.01 (0.064) | –0.542 (1.072) | 0.286 (1.043) |
| Kernel matching | –0.047 (0.061) | 0.007 (0.064) | –0.398 (1.141) | 0.158 (1.105) |
Note: Caliper is chosen as one-half of standard deviation of propensity score. Standard errors reported for nearest neighbor estimators are Abadie-Imbens (AI) robust standard errors. Standard errors reported for radius matching and kernel matching estimators are obtained from bootstrapping with 1,000 replications. No statistical significance at the 10%, 5%, and 1% levels.