# st: Interpreting missing standard errors, no z scores, etc. in stcox

 From "Douglas Thomas" <[email protected]> To <[email protected]> Subject st: Interpreting missing standard errors, no z scores, etc. in stcox Date Tue, 21 Oct 2003 10:14:31 -0600

Dear Statalist:

I am running Stcox and would really appreciate any help that someone what me able to provide. How does one interpret missing standard errors, misin z scores etc. When I run it, several of the variables, (e.g., "lang") come back with a hazard ratio but nothing else. I checked the Stata FAQ response. However, it is unclear to me if it best practice to leave those variables out. Are the results credible with some of the variables coming out like this. Also, many of the P values are coming back as 1.000. How does one interpret this result? Can I use/trust the overall results and the results of other variables?

Cox regression --
Breslow method for ties                Number of obs      =     22667
Gamma shared frailty                   Number of groups   =       103
Group variable: company

No. of subjects =         2163                  Obs per group: min =       194
No. of failures =           71                                 avg =   220.068
Time at risk    =      7739538                                 max =       395

Wald chi2(46)      =   6209.90
Log likelihood  =   -313.29552                  Prob > chi2        =    0.0000

------------------------------------------------------------------------------
_t | Haz. Ratio   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
pstock |   .9992232   .0121881    -0.06   0.949     .9756183    1.023399
mstock |     1.0124   .0179597     0.69   0.487     .9778044    1.048219
expstock |   1.094391   .1897217     0.52   0.603     .7791295    1.537218
grupo2 |   4.231667   2.718451     2.25   0.025     1.201417     14.9049
priv |   2.162367   1.563238     1.07   0.286      .524289    8.918421
alliance |   2.812804   1.462422     1.99   0.047     1.015281     7.79279
own2 |   1.310643   1.584542     0.22   0.823     .1225741    14.01427
lsales |   1.371852   .3741872     1.16   0.246     .8037721    2.341432
nf |   .9062903    .105697    -0.84   0.399     .7210994    1.139041
pre91 |   4.332353   1.997612     3.18   0.001     1.754857    10.69562
age |   .9949293   .0094322    -0.54   0.592     .9766132    1.013589
sic1 |   1.859124   2.472855     0.47   0.641     .1371227    25.20619
sic2 |   4.299693   4.926218     1.27   0.203     .4552019    40.61353
sic3 |   2.843917   3.657909     0.81   0.416     .2286034    35.37945
gdpcaph |   1.000517   .0005426     0.95   0.340     .9994545    1.001581
gdpdiff |          1   3.27e-07     0.25   0.802     .9999994    1.000001
lang |   1.17e+09          .        .       .            .           .
lndist |    1.38712   3.576611     0.13   0.899      .008858     217.215
agree |   .9933545   .6794694    -0.01   0.992     .2599379    3.796111
border |   4.169336   7.285759     0.82   0.414     .1357139    128.0884
lninfdi |   1.272696   .5410447     0.57   0.571     .5531771    2.928093
lnexport |   1.226262   .5871333     0.43   0.670     .4797653    3.134281
coun1 |   3.22e-08   .7510258    -0.00   1.000            0           .
coun2 |   3.94e+07   1.46e+08     4.72   0.000     27456.55    5.66e+10
coun3 |    3408175          .        .       .            .           .
coun4 |   2.17e+08   8.30e+08     5.02   0.000     120135.3    3.92e+11
coun6 |   6.54e+07   2.00e+08     5.87   0.000       160486    2.66e+10
coun7 |   5.03e-07   21.54161    -0.00   1.000            0           .
tarcou1 |   4.11e-18   1.44e-09    -0.00   1.000            0           .
tarcou2 |   .8961112   2.568654    -0.04   0.969     .0032542    246.7658
tarcou3 |    .302835    .835457    -0.43   0.665     .0013581    67.52881
tarcou4 |   .3512424   .8451288    -0.43   0.664     .0031443     39.2368
tarcou5 |   5.08e-18   1.86e-09    -0.00   1.000            0           .
tarcou6 |   7.41e-18   2.79e-09    -0.00   1.000            0           .
tarcou7 |   .5215511   1.251615    -0.27   0.786      .004727    57.54455
tarcou8 |   .2315671   .6427914    -0.53   0.598     .0010043    53.39115
tarcou9 |   6.90e-18   2.70e-09    -0.00   1.000            0           .
tarcou11 |   6.73e-18   2.16e-09    -0.00   1.000            0           .
tarcou12 |   3.20e-18   1.17e-09    -0.00   1.000            0           .
tarcou13 |   2.44e-18   8.51e-10    -0.00   1.000            0           .
tarcou15 |   2.15e-18   8.31e-10    -0.00   1.000            0           .
tarcou16 |   7.80e-18   2.98e-09    -0.00   1.000            0           .
tarcou17 |   1.043378   2.932431     0.02   0.988     .0042279    257.4887
tarcou18 |   4.31e-09   1.06e-08    -7.84   0.000     3.50e-11    5.32e-07
tarcou19 |   3.93e-09   9.88e-09    -7.69   0.000     2.84e-11    5.44e-07
tarcou20 |   3.63e-18   1.37e-09    -0.00   1.000            0           .
tarcou21 |   .4769469   1.298323    -0.27   0.786     .0022981    98.98547
tarcou22 |    .234499   .5961574    -0.57   0.568     .0016076    34.20708
-------------+----------------------------------------------------------------
theta |   .4990421   .4101498
------------------------------------------------------------------------------
Likelihood-ratio test of theta=0: chibar2(01) =     3.58 Prob>=chibar2 = 0.029

Note: Standard errors of hazard ratios are conditional on theta.

Thanks,

Doug Thomas

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