Table 2 Comparisons of covariates before and after matching (N = 54,398)
Variables | Mean | Reduction |bias| % | t-test | ||||
|---|---|---|---|---|---|---|---|
Treated | Control | %bias | t | p > t | |||
Male | U | 0.477 | 0.503 | −5.3 | 86.1 | −5.34 | 0.000 |
M | 0.477 | 0.473 | 0.7 | 0.97 | 0.333 | ||
Method of admission – First choice | U | 0.596 | 0.497 | 19.9 | 99.5 | 20.04 | 0.000 |
M | 0.596 | 0.595 | 0.1 | 0.13 | 0.896 | ||
Academic track of high school-Science | U | 0.652 | 0.728 | −16.3 | 94.2 | −16.13 | 0.000 |
M | 0.652 | 0.648 | 1.0 | 1.20 | 0.231 | ||
College entrance examination score | U | 86.111 | 86.260 | −1.1 | 43.0 | − 1.11 | 0.268 |
M | 86.118 | 86.330 | −1.6 | −2.07 | 0.038 | ||
Grade-Sophomores | U | 0.264 | 0.281 | −3.9 | 97.1 | −3.91 | 0.000 |
M | 0.264 | 0.264 | 0.1 | 0.15 | 0.881 | ||
Grade-Juniors | U | 0.238 | 0.256 | −4.1 | 88.6 | −4.16 | 0.000 |
M | 0.238 | 0.240 | −0.5 | −0.62 | 0.535 | ||
Grade-Seniors | U | 0.170 | 0.142 | 7.7 | 88.2 | 7.56 | 0.000 |
M | 0.170 | 0.173 | −0.9 | −1.14 | 0.256 | ||
Educational attainment - Fathers | U | 10.594 | 10.319 | 7.8 | 82.3 | 7.83 | 0.000 |
M | 10.594 | 10.545 | 1.4 | 1.79 | 0.073 | ||
Educational attainment - Mothers | U | 9.318 | 8.959 | 8.8 | 88.7 | 8.86 | 0.000 |
M | 9.317 | 9.277 | 1.0 | 1.30 | 0.193 | ||
ISEI of the father | U | 31.193 | 30.376 | 4.4 | 66.3 | 4.37 | 0.000 |
M | 31.186 | 30.912 | 1.5 | 1.91 | 0.056 | ||
ISEI of the mother | U | 27.106 | 26.312 | 5.0 | 71.5 | 5.01 | 0.000 |
M | 27.102 | 26.875 | 1.4 | 1.84 | 0.065 | ||
Family economic status – Middle | U | 0.333 | 0.340 | −1.4 | 82.2 | −1.36 | 0.175 |
M | 0.333 | 0.335 | −0.2 | −0.31 | 0.753 | ||
Family economic status – High | U | 0.114 | 0.107 | 2.0 | 54.2 | 1.98 | 0.047 |
M | 0.114 | 0.111 | 0.9 | 1.18 | 0.239 | ||
Home location – Urban area | U | 0.455 | 0.435 | 4.0 | 74.4 | 4.02 | 0.000 |
M | 0.455 | 0.450 | 1.0 | 1.34 | 0.181 | ||