survey weights

On Sun, 4 Sep 2005, A Das wrote:

Just: "missing values in object". That would imply

the

object was created. But then I write "dchina", and

it

says "object dchina not found".

No, it would not imply the object was created.  If
it was an error message 
(rather than a warning) the object would not have
been created.

I presume the full message was
  Error in na.fail.default(object) : missing values
in object

If so, it sounds as though you have missing values
in the id, weights, or 
strata variable.
    summary(China[,c("psu","stata","weight0x"])
will verify this.

Stata will just have dropped these observations (use
-svydes- to verify 
this).  If you want to drop the observations in R
you need to do this 
explicitly. Having missing data may be unavoidable,
but if you have 
observations in a sample it seems that you should
know how they were 
sampled.
To drop these observations you could use

obsChina <- subset(China, !is.na(psu) &
!is.na(strata) & !is.na(weight0x))

and then use obsChina rather than China in the
svydesign() function.

 	-thomas

                         -Bobby

--- Thomas Lumley <tlumley at u.washington.edu>

wrote:

On Sun, 4 Sep 2005, A Das wrote:

Thanks, Thomas.
   Yes, that's exactly what happened: the

warnings

came first after "data(China)", and then after
"dchina<-svydesign..." So the design object

isn't

being produced? The dataset is very large, and

the

weights were already set in Stata before

importing.

Would either of those cause problems?

Probably not.  What was the error message from
svydesign()?  That is what
will say what went wrong.

 	-thomas