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From |
Nick Winter <nw53@cornell.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Degrees of freedom formula for -svytab- |

Date |
Mon, 25 Oct 2004 13:25:23 -0400 |

Ironic.

It's been a while since I've mucked around under the hood with the -svy- commands (and with my -svr- commands). True enough.

--Nick

At 05:23 PM 10/25/2004 +0100, you wrote:

--------------------------------------------------------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 commandIt 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.

Best wishes

Roger

Nicholas Winter 607.255.8819 t

Assistant Professor 607.255.4530 f

Department of Government nw53@cornell.edu e

308 White Hall falcon.arts.cornell.edu/nw53 w

Cornell University

Ithaca, NY 14853-4601

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**References**:**st: Degrees of freedom formula for -svytab-***From:*Roger Newson <roger.newson@kcl.ac.uk>

**Re: st: Degrees of freedom formula for -svytab-***From:*Nick Winter <nw53@cornell.edu>

**Re: st: Degrees of freedom formula for -svytab-***From:*Roger Newson <roger.newson@kcl.ac.uk>

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