Dear Statalist:
I am trying to derive marginal effects after a probit estimation. I have survey data, so I use the "svyprobit" command after specifying weight, psu, and strata variables. I then use the "mfx" command and obtain the usual results.
However, when I use the "mfx" command after a simple probit estimation where I account for weights but ignore the survey design, I obtain very different marginal effects.
In Stata language, I am comparing:
svyprobit y x, subpop(sample)
mfx
probit y x if sample==1 [pweight=weight]
mfx
Is there a reason I should be obtaining different results from these commands? If so, which is correct? Any help will be appreciated.
Jason Murasko
Assistant Professor, Public & Environmental Affairs
Indiana University South Bend
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