Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

Re: st: RE: Egen command


From   "Ziad El-Khatib" <Ziad.El-Khatib@ki.se>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: Egen command
Date   Thu, 28 Aug 2008 10:26:05 -0700

Dear Eva & Nick,
Apologies to reply on For some strange reasons the email ended up in
spam box, also found some other email went there.

I have worked on it and it went well.
Will also try your kind suggestions.

Thank you and best regards
ziad


On Tue, Aug 19, 2008 at 11:09 AM, Nick Cox <n.j.cox@durham.ac.uk> wrote:
> Is this copied from a Stata dataset? Or from some spreadsheet or
> similar?
>
> You have five variables here but in most cases only three values are
> shown.
>
> What do the blanks mean?
>
> Eva's recent post may be what you want. I'm going off-line now.
>
> Nick
> n.j.cox@durham.ac.uk
>
> Ziad El-Khatib
>
> Dear Nick,
> Thank you.
>
> Compliance= whether patients did take their drugs within a certain
> range rate or not, defined as 95-110% of prescribed drugs on monthly
> basis, in this cohort.
>
> Kindly find below new example with pillcount variable.
>
> studyid visit   pillcount       pc2_24  pc36_104
>
> 1027    2       0
> 1027    4       0
> 1027    8       0
> 1027    12      0
> 1027    16      0
> 1027    20      0
> 1027    24      0                   0
> 1027    36      0
> 1027    52      0
> 1027    78      0                                   0
> 1029    2       0
> 1029    4       0
> 1029    8       0
> 1029    12      0
> 1029    16      0
> 1029    20      0
> 1029    24      0                   0
> 1029    36      0
> 1029    52      0
> 1029    78      1
> 1029    104     0                                   1
>
>
> ID 1027 did drop out before week 104 on treatment but still counted her.
> ID 1029 has example of patient coming to all visits.
>
>
>
> Hope this helps?
> Thank you again and best regards
> ziad
>
>
>
>
>
> On Tue, Aug 19, 2008 at 10:33 AM, Nick Cox <n.j.cox@durham.ac.uk> wrote:
>> You should keep away from -egen, count()-.
>>
>> What does the help say?
>>
>> count(exp) (allows by varlist:) creates a constant (within varlist)
>> containing the number of nonmissing observations of exp.
>>
>> Your exp (i.e. expression) is -pillcount-. So you are counting whether
>> -pillcount- is non-missing. 1 is non-missing. 0 is non-missing. Any
>> other non-missing value is non-missing. All observations with any of
>> these non-missing values will be counted.
>>
>> That is, I gather, not at all what you want.
>>
>> I am less able to work out precisely what you do want. I could make
> some
>> guesses but I think it is better if you explain. Do remember that many
>> of us are not biostatisticians or medics and so, like me, may be fuzzy
>> on what on earth compliance is.
>>
>> Your examples do not include any with data for the key variable
>> -pillcount-.
>>
>> Nick
>> n.j.cox@durham.ac.uk
>>
>> Ziad El-Khatib
>>
>> I have cohort dataset monitoring patients' compliance to drugs over 11
>> time points (weeks 2, 4, 8, 12, 16, 20, 24, 36, 52, 78 and 104 after
>> starting on drugs).
>> I want to look at the persistence of their compliance over weeks 2-24
>> versus 36-104, i.e. OR of not missing any pill at all over all this
>> visits between weeks 2-24 versus 36-104.
>>
>> At every visit I coded pillcount as 0/1: 1 if patient was not
>> compliant versus 0: if patient was compliant.
>>
>> Now trying to create pc2_24 for weeks 2 to 24, and pc36_104 for week
>> 36 to 104 to code them as 0/1 (compliant/not compliant).
>>
>> I tried
>> egen pc2_24=count(pillcount),by(studyid), if visit>0&visit<25
>>
>> So got
>>
>> studyid visit   pc2_24
>> 1003    2       1
>> 1003    4       1
>> 1003    8       1
>> 1003    12      1
>> 1003    16      1
>> 1003    20      1
>> 1003    24      1
>> 1005    2       1
>> 1005    4       1
>> 1005    8       1
>>
>>
>> But I want the result to look like:
>> studyid visit   pc2_24
>> 1003    2
>> 1003    4
>> 1003    8
>> 1003    12
>> 1003    16
>> 1003    20
>> 1003    24      1
>> 1005    2
>> 1005    4
>> 1005    8
>> 1005    12
>> 1005    16
>> 1005    20
>> 1005    24      1
>>
>>
>> so only to show number 0 or 1 at the last visit, whether visit number
>> 24, 20 , or else that is <24
>
> *
> *   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