Table 2

Difference-in-Difference Matching Results: Average Treatment Effects on Treated (ATT) for Columbia County

Outcome: Change in Land Cover Proportion, 2001–2012Treatment: Transactions from Farmers to Nonresidents
EstimatorOLS CoefficientRadius Match 1 (n=3, Caliper=0.01)Regression Adjustment with Matched Sample 1Radius Match 2 (n=5, Caliper=0.01)Regression Adjustment with Matched Sample 2Radius Match 3 (n=6, Caliper=0.01)Regression Adjustment with Matched Sample 3
ATT on Aga change−0.0896**−0.1258**−0.1208**−0.1105**−0.1132**−0.1141**−0.1168**
(0.0411)(0.0637)(0.0578)(0.0581)(0.0570)(0.0557)(0.0569)
ATT on hay change0.0724*0.1293*0.1293**0.1090*0.1139*0.1075*0.1124*
0 (0.0420)0 (0.0668)(0.0620)(0.0633)(0.0609)(0.0607)(0.0606)
ATT on mismatch change0.04790.08420.08370.06380.07090.06380.0716
(0.0381)(0.0573)(0.0529)(0.0551)(0.0533)0 (0.0518)(0.0531)
PS-test (B/R)41.00/.9141.0/0.9127.5/1.1327.5/1.1323.8/1.0023.8/1.00
N treated: on support (all)4946 (49)46 (49)46 (49)46 (49)46 (49)46 (49)
N control: matched (all)609104 (609)104 (609)155 (609)155 (609)179 (609)179 (609)
N total658150 (658)150 (658)201 (658)201 (658)225 (658)225 (658)
  • Note: Treatment: farmland transacted from residents to nonresidents between 2002 and 2010; control = farmland owned by residents throughout the study period. We use propensity matching with the radius set to 0.01. To implement the common support condition, we exclude three observations in the treatment group that do not satisfy that each treated has at least six nearest neighbors in the control group within the radius 0.01. We carry out two kinds of estimators based on matching with a different number of near neighbors (n = 3, 5, 6): radius matching (RM) and regression adjustment with the matched sample (RA). Bootstrapping (2,000 replications for RMs) or robust (for RAs) standard errors are in parentheses.

  • a Ag denotes agricultural land cover, except hay.

  • * p < 0.1;

  • ** p < 0.05;

  • *** p < 0.01.