help biasselect (Quantitative Bais Aanlysis in Epidemiology)

Title

biasselect -- performs bias analysis for selection bias

Syntax

biasselect
depvar indepvar
[if] [in]
[, options]

Options
pa(#) The selection proportion for a and the default is 0.90

pb(#) The selection proportion for b and the default is 0.80

pc(#) The selection proportion for c and the default is 0.76

pd(#) The selection proportion for d and the default is 0.60

generate generate newvar containing weight for each individual;

biasselecti
a b c d
[if] [in]
[, options]

Options
pa(#) The selection proportion for a and the default is 0.90

pb(#) The selection proportion for b and the default is 0.80

pc(#) The selection proportion for c and the default is 0.76

pd(#) The selection proportion for d and the default is 0.60

Description

Command biasselect, which is one of the commands among the package biasepi, performs bias analysis for the selection bias.

Combining the three commands (biasselect, biascon, biasmis) is able to perform bias analysis for selection.
Combining the existing Stata commands for probalistic distributions, biasselect is able to perform probalistic bias analysis

Options

pa specifies the selection proportion (pa>0 and pa<=1) for a and the default is 0.90

pb specifies the selection proportion (pb>0 and pb<=1) for b and the default is 0.80

pc specifies the selection proportion (pc>0 and pc<=1) for c and the default is 0.75

pd specifies the selection proportion (pd>0 and pd<=1) for d and the default is 0.60

generate generates newvar containing weight, which is the inverse of the selection proportion, for each individual

Examples

1. Simple bias analysis:

.biasselecti 232 133 4677 6031, pa(0.90) pb(0.80) pc(0.75) pd(0.60)

More examples

click on her

References

Lash, Timothy L., Fox, Matthew P., Fink, Aliza K. 2009.

Applying Quantitative Bias Analysis to Epidemiologic Data

The online resource for the reference textbook.

Author

Chunsen Wu, the University of Southern Denmark; Odense University Hospital, Denmark

cwu@health.sdu.dk

chunsen.wu@rsyd.dk

Also see

Help: biasepi, biasselect, biascon, biasmis, biassurv, biastab2

Stored results

biasselect and biasselecti store the following in r():

Scalars

r(RR_Observed) Risk ratio for the observed 2*2 table

r(OR_Observed) Odds ratio for the observed 2*2 table

r(RD_Observed) Risk difference for the observed 2*2 table

r(RR_Corrected) Risk ratio for the corrected 2*2 table

r(OR_Corrected) Odds ratio for the corrected 2*2 table

r(RD_Corrected) Risk difference for the corrected 2*2 table

r(RR_Missed) Risk ratio for the missed 2*2 table

r(OR_Missed) Odds ratio for the missed 2*2 table

r(RD_Missed) Risk difference for the missed 2*2 table

Matrices

r(O) Observed 2*2 table

r(C) Corrected 2*2 table

r(B) Bias parameters 2*2 table

r(M) Missed 2*2 table

r(R) RR, OR, and RD