How sensitive are matching estimates of active labor market policy effects to typically unobserved confounders?

Journal for Labour Market Research

Table 6 Estimated effects using other matching and weighting approaches

	Regular employment after 36 months			Real monthly earnings after 36 months
	Std.	Ext.	Diff.	Std.	Ext.	Diff.
Kernel matching (baseline)	0.063\(^{***}\)	0.056	0.006	118\(^{***}\)	109\(^{***}\)	9
Kernel matching (baseline)	(0.017)	(0.018)	(0.006)	(29)	(29)	(9)
Caliper radius matching	0.054\(^{***}\)	0.058\(^{***}\)	− 0.005	107\(^{***}\)	113\(^{***}\)	− 3
Caliper radius matching	(0.019)	(0.019)	(0.014)	(32)	(32)	(18)
Local linear matching	0.066\(^{***}\)	0.060\(^{***}\)	0.006	124\(^{***}\)	116\(^{***}\)	8
Local linear matching	(0.018)	(0.018)	(0.006)	(29)	(30)	(9)
Inverse probability weighting	0.063\(^{***}\)	0.057\(^{***}\)	0.006	117\(^{***}\)	111\(^{***}\)	7
Inverse probability weighting	(0.017)	(0.017)	(0.004)	(28)	(29)	(7)
Doubly robust	0.058\(^{***}\)	0.054\(^{***}\)	0.005	110\(^{***}\)	104\(^{***}\)	6
Doubly robust	(0.017)	(0.017)	(0.004)	(28)	(28)	(7)
Control variables
Typically observed covariates	\(\checkmark\)	\(\checkmark\)		\(\checkmark\)	\(\checkmark\)
Typically unobserved covariates		\(\checkmark\)			\(\checkmark\)

This table shows estimated ATTs. Standard errors are obtained via bootstrapping with 999 replications. Statistical significance based on the normal approximation on the 10/5/1% level is indicated by \(^{*}/^{**}/^{***}\). Local linear matching use a standard bandwidth of 0.06. The caliper for the radius matching is set equal to three times the 90% quantile of the distribution of differences in the propensity score from a nearest neighbor matching with replacement (Huber et al. 2015). The doubly robust estimator combines inverse probability weighting with parametric outcome adjustment (Robins et al. 1995)