Hi all,
As I finish polishing the functionality of a new command I have been programming (coming shortly I hope), I am wondering if there is a particular functionality for the offset(varname) option that cannot be equally obtained with the use of constraints. Consider the following
You can see how the results using offset and the constraint are identical, so it baffles me.
Thanks for throwing any light.
Alfonso.
As I finish polishing the functionality of a new command I have been programming (coming shortly I hope), I am wondering if there is a particular functionality for the offset(varname) option that cannot be equally obtained with the use of constraints. Consider the following
Code:
. clear all . set more off . sysuse auto (1978 Automobile Data) . gen wgt = -weight/1000 . const def 1 wgt = 1 . probit foreign mpg wgt, nolog Probit regression Number of obs = 74 LR chi2(2) = 36.38 Prob > chi2 = 0.0000 Log likelihood = -26.84419 Pseudo R2 = 0.4039 ------------------------------------------------------------------------------ foreign | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- mpg | -.1039503 .0515689 -2.02 0.044 -.2050235 -.0028772 wgt | 2.335544 .56605 4.13 0.000 1.226107 3.444982 _cons | 8.275464 2.554142 3.24 0.001 3.269437 13.28149 ------------------------------------------------------------------------------ . probit foreign mpg, offset(wgt) nolog Probit regression Number of obs = 74 Wald chi2(1) = 0.00 Log likelihood = -30.278258 Prob > chi2 = 0.9718 ------------------------------------------------------------------------------ foreign | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- mpg | .0010781 .0304492 0.04 0.972 -.0586012 .0607575 _cons | 2.280349 .7161614 3.18 0.001 .8766982 3.683999 wgt | 1 (offset) ------------------------------------------------------------------------------ . probit foreign mpg wgt, const(1) nolog Probit regression Number of obs = 74 Wald chi2(1) = 0.00 Log likelihood = -30.278258 Prob > chi2 = 0.9718 ( 1) [foreign]wgt = 1 ------------------------------------------------------------------------------ foreign | Coef. Std. Err. z P>|z| [95% Conf. Interval] -------------+---------------------------------------------------------------- mpg | .0010781 .0304492 0.04 0.972 -.0586012 .0607575 wgt | 1 (constrained) _cons | 2.280349 .7161614 3.18 0.001 .8766981 3.683999 ------------------------------------------------------------------------------
Thanks for throwing any light.
Alfonso.
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