Hello statalisters:
I have estimated probabilities for two groups (e.g., exposed and
unexposed) using the "adjust" command after a logistic regression,
holding several other covariates to their mean or other specified
values. The main exposure varies among individuals and is continuous.
I would like to estimate the risk difference for these each individual
(p_exposed-p_unexposed) and the confidence limit for this estimate.
P_unexposed is constant for all unexposed. The risk difference is no
problem, simply p_exposed-p_unexposed but I can't figure out how to
get the confidence limits or standard error. A partial line listing of
the predicted values follows, xse is the standard error of the linear
predictor (not of the probability). The only other option I could
think of would be to manually input the mean and other values get the
estimates and their ci's using predictnl. Does anyone have any other
suggestions? Thanks much, Tim
+--------------------------------------------+
| xse pexposed punexposed rd|
|--------------------------------------------|
6723. | .0398789 .0903156 .0657542 .0245614 |
6724. | .0305243 .0843028 .0657542 .0185485 |
6725. | .0305078 .0845024 .0657542 .0187482 |
6726. | .0387372 .0898956 .0657542 .0241414 |
6727. | .0514583 .0940445 .0657542 .0282903 |
|--------------------------------------------|
6728. | .0317862 .0825899 .0657542 .0168356 |
6729. | .0333452 .081623 .0657542 .0158687 |
6730. | .0412409 .0907973 .0657542 .025043 |
6731. | .031887 .0825144 .0657542 .0167601 |
6732. | .031646 .0826999 .0657542 .0169456 |
|--------------------------------------------|
6733. | .0646825 .0978708 .0657542 .0321165 |
6734. | .0308402 .0835395 .0657542 .0177852 |
6735. | .032705 .0871379 .0657542 .0213836 |
6736. | .0450769 .092074 .0657542 .0263198 |
6737. | .0773924 .101446 .0657542 .0356918 |
|--------------------------------------------|
6738. | .0691182 .0991227 .0657542 .0333685 |
6739. | .0319578 .0824629 .0657542 .0167086 |
6740. | .0409456 .0787344 .0657542 .0129802 |
6741. | .0308616 .0835082 .0657542 .017754 |
6742. | .0317862 .0825899 .0657542 .0168356 |
|--------------------------------------------|
6743. | .0427944 .0913264 .0657542 .0255721 |
6744. | .0319578 .0824629 .0657542 .0167086 |
6745. | .0305152 .084671 .0657542 .0189167 |
6746. | .0360888 .0803978 .0657542 .0146436 |
6747. | .0441936 .0777828 .0657542 .0120286 |
|--------------------------------------------|
6748. | .0320302 .0824114 .0657542 .0166572 |
6749. | .0328664 .081885 .0657542 .0161308 |
6750. | .0310857 .0858377 .0657542 .0200834 |
6751. | .0334266 .0875607 .0657542 .0218065 |
6752. | .0306719 .0838315 .0657542 .0180772 |
|--------------------------------------------|
6753. | .032705 .0871379 .0657542 .0213836 |
6754. | .1031885 .0653001 .0657542 -.0004541 |
6755. | .0773924 .101446 .0657542 .0356918 |
6756. | .0373729 .0799165 .0657542 .0141622 |
6757. | .0374146 .0893851 .0657542 .0236308 |
|--------------------------------------------|
6758. | .0323203 .0822162 .0657542 .016462 |
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