Evaluation of the Australian Wage Subsidy Special Youth ...

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Table 4.7 Matching results, All-Within- caliper/Radius with replacement
Match
with
caliper
width
0.001
Match
with
caliper
width
0.005
Match
with
caliper
width
0.01
Match
with
caliper
width
0.02
Match
with
caliper
width
0.05
Difference in employment 90 for 0.14 0.17 0.17 0.16 0.15
matched treated and comparisons
F statistic 91 13.3 13.5 16.7 15.3 14.1
df
Number of SYETP matched 87 101 102 103 104
Number of comparison which satisfy 462 886 917 918 920
the caliper rule
Number of comparisons unmatched 458 34 3 2 0
Mean Standardized bias calculation 8.18 6.89 7.72 7.84 7.77
after matching 92
4.10 Discussion
The PSM results are now compared to those found for the Heckman bivariate normal
selection model in the earlier replication chapter. Earlier, the difficulty of which PSM
result to choose was addressed. The 0.001 caliper result was chosen as the result for
comparison upon the basis that it had no great deterioration in performance but covered
all SYETP cases. This facilitates similarity of conditions with the Heckman result.
We need to compare the marginal effect of SYETP in the Heckman probit to the
matching measure to make a common measure of the mean effect of treatment on the
treated. The Table 4.8 shown below contains these estimates and their statistical
significance. Both methods find a positive statistically significant effect on postprogramme
employment from participation in SYETP. The difference between the
employment gain estimated from the two different methods is however quite large.
Whereas for the Heckman bivariate probit the employment gain is closer to 30 percentage
points, for PSM the employment gain is estimated as closer to 20 percentage points.
90 Ever employed in 1986 survey.
91 Degrees of freedom df=n-1, n=number of matched treated and untreated. The t statistic is not produced
for this type of PSM.
92 For all variables entering the probit of SYETP participation.