Re: st: Subgroup analysis

[David Bell <dcbell@iupui.edu>]

So how large is your African American subsample?  Maybe your power is much lower in that subsample.  Or maybe your model is well specified for Whites but not for African Americans.

Dave
====================================
David C. Bell
Professor of Sociology
Indiana University Purdue University Indianapolis (IUPUI)
(317) 278-1336
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On Jul 7, 2010, at 2:35 PM, David Bai wrote:

> Hi, all,
>     I would like to compare predictors' effects across different racial/ethnic groups, so I first ran a comprehensive model including all groups, and then used subpop function in stata to do subpopulation analyses for each ethnic group.
>    What the results show is that many (not just a few) significant predictors in the comprehensive model (including all racial groups) become non-significant in the African American group, while the White group's results are similar to the results of the comprehensive model. How can I interpret all these? Is it possibly because African Americans are very homogeneous in the distributions of these predictors, and therefore it is hard for the analysis to distinguish any variations in the effects and therefore find non-significance in the results? Or is it because the sample size of this group is relatively small compared with other groups (e.g., whites)  in the sample? Are there any other possible interpretations? Your insight will be appreciated.
> 
>      David B
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