Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Interpretation of regressionmodel of ln-transformed variable


From   "roland andersson" <rolandersson@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Interpretation of regressionmodel of ln-transformed variable
Date   Wed, 5 Nov 2008 16:35:34 +0100

Thanks a lot. I learned a lot by these examples.

Sorry Your first name sounded danish - did not look to well on the adress.

Greetings
Roland

2008/11/5 Maarten buis <maartenbuis@yahoo.co.uk>:
> Sounds correct (though I can only certify the parts of the message in
> English or Stata)
>
> -- Maarten
>
> --- roland andersson <rolandersson@gmail.com> wrote:
>
>> Maarten
>>
>> Det er jo glimrende o dejlig
>>
>> Just to assure I have understood. In this model I keep age 10-19 and
>> non-perforated appendicitis (the largest groups) as reference level
>> so
>> I do not bother with mean centering with age.
>>
>>
>> lnLOS              exp(b)       Std. Err.      t        P>t
>> [95% Conf. Interval]
>>
>> lapscopy         1.015229   .0069404     2.21   0.027     1.001716
>> 1.028924
>> _Iappdgn2_1    1.854565   .0133561    85.76   0.000     1.828571
>> 1.880929
>> _Iappdgn2_3    1.172527   .0139403    13.39   0.000      1.14552
>> 1.200171
>> _Ialderkat_0     1.113349   .0124712     9.59   0.000     1.089172
>> 1.138063
>> _Ialderka~20    .9669727   .0081023    -4.01   0.000     .9512217
>> .9829846
>> _Ialderka~30    1.013716   .0091096     1.52   0.130     .9960177
>> 1.03173
>> _Ialderka~40    1.074382   .0115025     6.70   0.000     1.052072
>> 1.097165
>> _Ialderka~50    1.181179   .0134386    14.64   0.000      1.15513
>> 1.207815
>> _Ialderka~60    1.309059   .0192205    18.34   0.000     1.271924
>> 1.347279
>> _Ialderka~70    1.685401   .0312085    28.19   0.000     1.625328
>> 1.747694
>> _Ialderka~80    2.303874   .0611701    31.43   0.000     2.187045
>> 2.426943
>> prepermalign    1.190686    .027653     7.51   0.000     1.137701
>> 1.24614
>> precardios~s    1.024731   .0266026     0.94   0.347     .9738935
>> 1.078222
>> preperlung~d    1.076669   .0182661     4.35   0.000     1.041456
>> 1.113073
>> preperhype~i    1.024272   .0208447     1.18   0.239     .9842196
>> 1.065954
>> preperhjar~t     1.293909   .0480737     6.94   0.000     1.203033
>> 1.391651
>> prepernjur~t     1.050412   .0516992     1.00   0.318      .953814
>> 1.156792
>> preperdiab~s    1.168423   .0287019     6.34   0.000     1.113499
>> 1.226055
>> cons                1.858693   .0106446   108.24   0.000     1.837946
>>   1.879675
>>
>> And here I calculate the effect of laparoscopy
>>
>> . nlcom exp((_b[cons]+ _b[lapscopy]) -  exp((_b[cons])))
>>
>> _nl_1:  exp((_b[cons]+ _b[lapscopy]) - exp((_b[cons])))
>>
>>
>> vtidln       Coef.   Std. Err.      t    P>t     [95% Conf. Interval]
>>
>> _nl_1    .2941382   .0027509   106.92   0.000     .2887463
>> .2995302
>>
>> ie open appendectomy in nonperforated patients age 10-19 have a
>> geometric mean LOS of 1.86 (95% CI 1.83-1.88) days after adjustment
>> for comorbidity and lapscopy patients have 0.29 (95% CI 0.28-0.30)
>> days longer LOS.
>>
>> Correct?
>>
>> Greetings o stort tack
>>
>> Roland Andersson
>
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> visiting address:
> Buitenveldertselaan 3 (Metropolitan), room N515
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
>
>
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
>
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index