Table 5.
Estimation Results B IBC Version of Mullahy=s Birthweight Model
2SPS IBC | 2SRI IBC | |||
---|---|---|---|---|
Variable | Coeff | t-stat | Coeff | t-stat |
CONSTANT | 58.96 | 22.07 | 1.27 | 215.33 |
CIGSPREG | −1.92 | −3.47 | −0.004 | −3.52 |
PARITY | 3.23 | 3.26 | 0.01 | 3.39 |
WHITE | 9.64 | 4.85 | 0.02 | 4.64 |
MALE | 4.64 | 2.81 | 0.01 | 2.93 |
First-stage Residual (xu) | B | B | 0.024 | 2.03 |
Box-Cox | 5.20 | B | −0.95 | B |
Parameter τ E[y0]− E[y20] | 1.85 | 1.41 |
Second and fourth columns, respectively, give the estimates of the parameters in equations (18) and (19). Last row shows the 2SPS and 2SRI estimated effects of an exogenously imposed one-pack per day reduction in smoking, respectively.