st: svy + aweights

[Jeph Herrin <stata@spandrel.net>]

I am analyzing NHANES data (see manual page for -svyset-) using -svy-
commands. My complication is that I am using the subset of subjects for
which there is activity monitoring, and the number of days monitored varies
from 1 to 8. So - to be clear - for some subjects I have 1 day of monitoring,
and for some I have 2 days, some I have 3, etc. My dependent variable of
interest is daily average activity levels, but I would like this to be
weighted by the number of days monitored. (This is important because there
seems to be a clear relationship between days monitored and age, race, etc).

How do I incorporate this additional level of weighting? For instance,
if I use

  svy : mean depvar [aw=days]

I get an error that weights are not reported.

thanks,
Jeph
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