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Re: st: Degrees of freedom formula for -svytab-
At 16:54 25/10/2004, Nick Winter wrote:
This is the case for -svymean-, -svyratio- and -svytotal- if the user
specifies the -complete- option. However, if the user specifies the
-available- option, then the number of PSUs can be different for different
parameters, and therefore the degrees of freedom is a vector (with the same
dimensions as the estimated parameter), and its value can be calculated
from the estimation results by the command
It looks to me like the -svy- commands do, in fact, return the df in e(df_r).
This df is, in fact, e(N_psu) - e(N_strata). But you can just grab e(df_r).
matrix define dof = (e(_N_psu)-e(_N_str))'
I have just referred back to the -parmest- update in which I introduced the
ability to handle vector degrees of freedom (dated 11 November 2002), and,
according to my records, it was Nick Winter who told me this (in his email
dated 6 November 2002). Thanks again to Nick for that.
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