Hi there,
I try to create two similar cross-cultural sub samples with MatchIt and it
does not work. Perhaps, someone
can lead me in the right direction.
I have two samples that differ on some occupational data (mainly pay and job
experience in years).
However using MatchIt gives warning I cannot understand:
Warnmeldungen:
1: glm.fit: fitted probabilities numerically 0 or 1 occurred
2: In matchit2nearest(c(0L, 0L, 0L, 0L, 0L, 1L, 1L, 0L, 0L, 0L, 0L, :
Fewer control than treated units and matching without replacement. Not
all treated units will receive a match. Treated units will be matched in
the order specified by m.order: largest
The summary is:
Summary of balance for all data:
Means Treated Means Control SD Control Mean Diff eQQ Med eQQ Mean
eQQ Max
distance 0.7093 0.3053 0.2914 0.4040 0.4380 0.4043
0.6404
pay 2.1186 6.5809 8.4825 -4.4623 2.8806 4.5098
61.3719
jexp 10.4596 17.2035 12.3805 -6.7439 6.6000 6.8369
19.5000
hours02 44.1827 48.2222 10.3129 -4.0395 5.0000 4.7020
10.0000
Summary of balance for matched data:
Means Treated Means Control SD Control Mean Diff eQQ Med eQQ Mean
eQQ Max
distance 0.7354 0.3053 0.2914 0.4301 0.4707 0.4318
0.6576
pay 1.9540 6.5809 8.4825 -4.6269 2.9806 4.6529
65.9736
jexp 9.9540 17.2035 12.3805 -7.2495 6.8000 7.2495
19.0000
hours02 44.3990 48.2222 10.3129 -3.8232 5.0000 4.6414
10.0000
Percent Balance Improvement:
Mean Diff. eQQ Med eQQ Mean eQQ Max
distance -6.4478 -7.4715 -6.7965 -2.6742
pay -3.6892 -3.4715 -3.1715 -7.4980
jexp -7.4968 -3.0303 -6.0353 2.5641
hours02 5.3545 0.0000 1.2889 0.0000
Sample sizes:
Control Treated
All 198 208
Matched 198 198
Unmatched 0 10
Discarded 0 0
Thanks in advance,
Holger
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