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st: RE: Re: Variable estimates from GLST metaregression of observational studies


From   "G Livesey" <glivesey@inlogic.co.uk>
To   <statalist@hsphsun2.harvard.edu>, "'Nicola Orsini'" <Nicola.Orsini@ki.se>
Subject   st: RE: Re: Variable estimates from GLST metaregression of observational studies
Date   Sun, 10 May 2009 16:44:41 +0100

Dear Nicola,

Many thanks for these solutions. I confirm that both work with the larger
dataset I use. 

Geoff. L.



-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nicola Orsini
Sent: 09 May 2009 14:02
To: statalist@hsphsun2.harvard.edu
Subject: st: Re: Variable estimates from GLST metaregression of
observational studies


Dear Geoff,

thanks for explaining the problem.

The problem is not related to the selection of observations to be  
included in the analysis (`touse' and `if' work as intended).

The problem is to keep the actual order of the selected observations  
within each study when pooling multiple studies. I modified one line  
of the -glst- command to address this point.
I will post a revised ado file on both SSC and SJ archives.

In the meantime, -sort- the dataset before running -glst- command with  
multiple studies
or as alternative use the option tstage() which is not affected by - 
sort-.

* Solution 1

sort study_id , stable

glst ln_rr_m dosage if collecc==1, ///
se(se_glst) cov(person_y case) pfirst(study_id study_e)

* Solution 2

glst ln_rr_m dosage if collecc==1, ///
se(se_glst) cov(person_y case) pfirst(study_id study_e) ts(f)


Nicola



On May 7, 2009, at 5:19 PM, G Livesey wrote:

>
> Dear Nicola and Statalisters,
>
> I am getting different estimates each time I run a glst command on
> the same
> dataset in Stata and would be glad of suggestions of how to resolve  
> the
> problem.
>
> The glst command is used here to estimate the dose-dependency of
> effect in
> observational or relative risk data.
>
> The command and syntax, and extract from a dataset in use are shown
> below.
>
> I am using Stata v9.2, an up-to-date version of glst and the log data 
> (ln_rr_m  and corresponding errors se_glst) were obtained with gen
> double.
>
> I would very much appreciate help with this crucial problem.
>
> With thanks,
> Geoff. Livesey
>
>
> COMMAND AND SYNTAX:
> glst ln_rr_m dosage if  collect_c==1, se(se_glst) cov(person_y case) 
> pfirst(study_id studyexpression) random
>
>
> DATA:
>   ln_rr_m   dosage  collec~c  se_glst  person_y case study_id study_e
>         0         0      1          0    39637    281       3     2
> -.0725707  1.330824      1  .09000712    40218    265       3     2
> -.1278334  2.439844      1  .09273151    40621    241       3     2
> -.2613648  4.103374      1  .09935509    40956    198       3     2
> -.4462871  7.430433      1  .10182739    41222    156       3     2
>
>         0         0      1          0   145258    219       7     2
> -.1625189  1.212121      1  .10710753   141933    162       7     2
> -.1392621  2.203856      1  .11429413   139945    151       7     2
> -.198451   3.636364      1  .11990109   146011    132       7     2
> -.4462871  7.493112      1  .14876455   143153     77       7     2
>
>         0         0      1          0    34750    204       8     2
> -.1508229  2.187076      1  .10585496    35154    164       8     2
> -.0618754  3.827383      1  .10787362    35196    172       8     2
> -.1625189  5.649946      1  .11324987    35488    156       8     2
> -.328504   9.112817      1  .12940233    35529    148       8     2
>
>         0         0      1          0    23988    456       9     2
> -.0943106  1.14482       1  .07583086    25050    381       9     2
> -.1165338  2.289639      1  .08001615    24227    357       9     2
> -.1863296  3.663423      1  .03711996    26115    386       9     2
>
>
>
>
>
>
>
>

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