Re: st: svy, subpop ( ) with version 10

[Steven Samuels <sjhsamuels@earthlink.net>]

The numbers of PSU and strata (before subsetting) are different.  
Therefore either the -svyset- commands or the data sets differ.  By  
the way, how did you resolve your cluster problem?

Steven
On Jun 6, 2008, at 8:04 PM, Leda Inga wrote:


> Hi,
>
> I'm running a logit using svy and found a difference in the
> coefficients and pvalues reported by version 9 and 10 of Stata. I
> thought that it could be because of the observations that each one
> takes into account. As you can see below the version 10 considers 4178
> observations but  there are actually 8471 and the results are the same
> as using the "if" after svy. Can anybody explain this?
>
> The command I used for both versions was:
>
> svy, subpop(urbano): logit PS n_hijos educ seguro V157 NSE rural
> _ISREGION_3 _ISREGION_5 CPci CPci2 labor_prol
>
> VERSION 10:
>
> Survey: Logistic regression
>
> Number of strata   =        24                  Number of obs       
> =      4178
> Number of PSUs   =       451                 Population size    =  
> 2920.9792
>
>                             Subpop. no. of obs =      4178
>                                                           Subpop. size
>       = 2920.9792
>                                                           Design df
>       =       427
>                                                           F(  10,
> 418)    =     30.43
>                                                           Prob > F
>       =    0.0000
>
> ---------------------------------------------------------------------- 
> --------
>              |             Linearized
>           PS |      Coef.   Std. Err.      t    P>|t|     [95%  
> Conf. Interval]
> ------------- 
> +----------------------------------------------------------------
>      n_hijos |  -.0627022   .0233953    -2.68   0.008    -. 
> 1086865   -.0167179
>         educ |   .0995025   .0176722     5.63   0.000     . 
> 0647671    .1342379
>       seguro |   .2691795   .1430446     1.88   0.061    -. 
> 0119797    .5503387
>         V157 |   .2184025   .0961237     2.27   0.024     . 
> 0294679    .4073371
>          NSE |   .5893834   .0859681     6.86   0.000     . 
> 4204101    .7583568
> _ISREGION_3 |  -.8503491   .2073588    -4.10   0.000     -1.25792    
> -.4427781
> _ISREGION_5 |  -.7629466   .2529318    -3.02   0.003    -1.260093    
> -.2658003
>         CPci |    .298412   .0547975     5.45   0.000     . 
> 1907057    .4061184
>        CPci2 |  -.0109094   .0043379    -2.51   0.012    -. 
> 0194356   -.0023832
>   labor_prol |    .415821   .1035528     4.02   0.000     . 
> 2122843    .6193578
>        _cons |  -2.961981   .3026012    -9.79   0.000     
> -3.556754   -2.367207
> ---------------------------------------------------------------------- 
> --------
> Note: 25 strata omitted because they contain no subpopulation members.
>
>
> VERSION 9:
>
> Survey: Logistic regression
>
> Number of strata   =        49                  Number of obs       
> =      8471
> Number of PSUs   =      1118                 Population size    =   
> 6948.092
>                                                           Subpop. no.
> of obs =      4212
>                                                           Subpop. size
>       = 2945.3116
>                                                           Design df
>       =      1069
>                                                           F(  10,
> 1060)    =     31.19
>                                                           Prob > F
>       =    0.0000
>
> ---------------------------------------------------------------------- 
> --------
>              |             Linearized
>           PS |      Coef.   Std. Err.      t    P>|t|     [95%  
> Conf. Interval]
> ------------- 
> +----------------------------------------------------------------
>      n_hijos |  -.0624413    .023198    -2.69   0.007      -. 
> 10796   -.0169225
>         educ |    .100353   .0178213     5.63   0.000     . 
> 0653842    .1353218
>       seguro |   .2789113   .1415214     1.97   0.049     . 
> 0012202    .5566025
>         V157 |   .2192173   .0962575     2.28   0.023     . 
> 0303421    .4080924
>          NSE |   .5896208   .0851999     6.92   0.000     . 
> 4224427    .7567989
> _ISREGION_3 |  -.8230625   .2058183    -4.00   0.000    -1.226916    
> -.4192088
> _ISREGION_5 |  -.7412179   .2491071    -2.98   0.003    -1.230012    
> -.2524236
>         CPci |   .2921813     .04976     5.87   0.000      . 
> 194543    .3898195
>        CPci2 |  -.0103967   .0037064    -2.81   0.005    -. 
> 0176694    -.003124
>   labor_prol |   .4267068   .1025795     4.16   0.000     . 
> 2254268    .6279867
>        _cons |   -2.97932    .293572   -10.15   0.000     
> -3.555362   -2.403277
> ---------------------------------------------------------------------- 
> --------
>
>
> Thanks.
> *
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