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RE: st: RE: AW: RE: Evaluating a set of conditions


From   "Martin Weiss" <martin.weiss1@gmx.de>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: RE: AW: RE: Evaluating a set of conditions
Date   Thu, 24 Jun 2010 00:22:33 +0200

<>

In your -input- call, the "disease" variable seems to be missing. 

Anyway, if the only problem is with a certain combination, why not add

***********
replace test=. if a==1 & missing==3
***********


HTH
Martin

-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Thomas Speidel
Sent: Donnerstag, 24. Juni 2010 00:09
To: statalist@hsphsun2.harvard.edu
Subject: RE: st: RE: AW: RE: Evaluating a set of conditions

Forcing myself to use -cond-, I get one step closer, yet not quite there
yet:
(in the code below I added one more obs at id==19)

======================
input byte(id a b c d e disease)
  1   0   0   1   0   0
  2   1   0   1   1   0
  3   .   1   1   1   1
  4   0   1   1   0   1
  5   1   0   0   0   0
  6   1   .   1   1   0
  7   0   0   0   0   0
  8   1   .   .   .   1
  9   1   0   0   0   0
10   1   .   .   1   1
11   1   .   1   0   0
12   1   0   1   0   0
13   1   0   1   0   0
14   .   0   1   0   0
15   1   0   1   0   0
16   1   0   1   1   0
17   0   0   1   0   0
18   1   .   .   0   .
19   0   .   .   .   1
end

egen missing = rowmiss(b c d e)
gen byte test =cond(missing(a), ., cond(a==1, cond(missing<=1, (b + c  
+ d + e)>=2, cond((b + c + d + e)>=2, 1, .)), 0))

. assert disease==test
3 contradictions in 19 observations
assertion is false
=======================
this seems to fail whenever a==1 & missing==3

Thomas

Quoting Thomas Speidel <thomas@tmbx.com> Wed 23 Jun 13:13:54 2010:

> While trying to simplify the problem for the list (my variables are  
> not actually called a, b, c, etc) I must have inadvertantly  
> introduced some problems.  Sorry for the confusion.
>
> Nonetheless, the variable called "disease" in the n=18 dataset is  
> indeed what I am trying to achieve.
>
> Thomas
>
> Quoting Martin Weiss <martin.weiss1@gmx.de> Wed 23 Jun 13:02:40 2010:
>
>>
>> <>
>>
>> Your own code returns "1" for id==11. Have you changed your mind?
>>
>> ***********
>> clear*
>>
>> inp byte(id  a b c d e)
>> 1   0   0   1   0   0
>> 2   1   0   1   1   0
>> 3   .   1   1   1   1
>> 4   0   1   1   0   1
>> 5   1   0   0   0   0
>> 6   1   .   1   1   0
>> 7   0   0   0   0   0
>> 8   1   .   .   .   1
>> 9   1   0   0   0   0
>> 10   1   .   .   1   1
>> 11   1   .   1   0   0
>> 12   1   0   1   0   0
>> 13   1   0   1   0   0
>> 14   .   0   1   0   0
>> 15   1   0   1   0   0
>> 16   1   0   1   1   0
>> 17   0   0   1   0   0
>> 18   1   .   .   0   .
>> end
>>
>> egen anytwo = rowtotal(a b c d e), missing
>> egen missing = rowmiss(a b c d e)
>> replace anytwo = . if (anytwo==0 & missing>=2 & missing<.)
>> replace anytwo = . if (anytwo==1 & missing==1)
>> replace anytwo = . if (anytwo==1 & missing==3)
>> replace anytwo = . if (missing>=4)
>> gen disease = 1 if (a==1 & anytwo>=2 & anytwo<.)
>> replace disease = 0 if (a==1 & anytwo<2)
>> replace disease = 0 if a==0
>> replace disease =. if a==.
>>
>>
>> list in 11, noo
>> ***********
>>
>>
>> HTH
>> Martin
>>
>> -----Original Message-----
>> From: owner-statalist@hsphsun2.harvard.edu
>> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Thomas Speidel
>> Sent: Mittwoch, 23. Juni 2010 17:10
>> To: statalist@hsphsun2.harvard.edu
>> Subject: Re: st: RE: AW: RE: Evaluating a set of conditions
>>
>> Thanks Martin and Nick.  Here is an example where I have added more
>> missing and manually created "disease" to clarify how the missing
>> would impact the results:
>>
>>     id   a   b   c   d   e   disease
>>      1   0   0   1   0   0         0
>>      2   1   0   1   1   0         1
>>      3   .   1   1   1   1         .
>>      4   0   1   1   0   1         0
>>      5   1   0   0   0   0         0
>>      6   1   .   1   1   0         1
>>      7   0   0   0   0   0         0
>>      8   1   .   .   .   1         .
>>      9   1   0   0   0   0         0
>>     10   1   .   .   1   1         1
>>     11   1   .   1   0   0         .
>>     12   1   0   1   0   0         0
>>     13   1   0   1   0   0         0
>>     14   .   0   1   0   0         .
>>     15   1   0   1   0   0         0
>>     16   1   0   1   1   0         1
>>     17   0   0   1   0   0         0
>>     18   1   .   .   0   .         .
>>
>> Take a look at id==11 for example, where I don't have enough
>> information to determine disease presence.
>>
>> Thomas Speidel
>>
>> Quoting Nick Cox <n.j.cox@durham.ac.uk> Wed 23 Jun 06:59:44 2010:
>>
>>> Yes, if there are missings it's more complicated than my initial answer
>>> could suggest.
>>>
>>> (a == 1) & (((b == 1) + (c ==1) + (d == 1) + (e == 1)) >= 2)
>>>
>>> would seem to match the possibilities better.
>>>
>>> Nick
>>> n.j.cox@durham.ac.uk
>>>
>>> Martin Weiss
>>>
>>> The result does seem to differ much, though, from the one Thomas
>>> evidently
>>> wants - as expressed by his example:
>>>
>>> *************
>>> clear*
>>> set obs 10000
>>> set seed 12345
>>>
>>> foreach var of newlist a b c d e{
>>> 	gen byte `var'=runiform()<.5
>>> 	replace `var'=. if runiform()<.15
>>> }
>>>
>>> //NJC
>>> gen disease_true = a & (b + c + d + e >= 2) /*
>>> */  if !missing(a, b, c, d, e)
>>>
>>> //Thomas
>>> egen anytwo = rowtotal(a b c d e), missing
>>> egen missing = rowmiss(a b c d e)
>>> replace anytwo = . if (anytwo==0 & missing>=2 & missing<.)
>>> replace anytwo = . if (anytwo==1 & missing==1)
>>> replace anytwo = . if (anytwo==1 & missing==3)
>>> replace anytwo = . if (missing>=4)
>>> gen disease = 1 if (a==1 & anytwo>=2 & anytwo<.)
>>> replace disease = 0 if (a==1 & anytwo<2)
>>> replace disease = 0 if a==0
>>> replace disease =. if a==.
>>>
>>> //Comparison
>>> compare disease_true disease
>>> as  disease_true ==disease
>>> *************
>>>
>>> Nick Cox
>>>
>>> I think you need to be clear whether missing means true, false or
>>> indeterminate as far as this is concerned.
>>>
>>> Setting aside missings, as a, b, c, d, e are Booleans (1 = true, 0 =
>>> false) then
>>>
>>> gen disease_true = a & (b + c + d + e >= 2)
>>>
>>> is one way to do it. If missings make the problem indeterminate then
>>> tack on
>>>
>>> ... if !missing(a, b, c, d, e)
>>>
>>> Nick
>>> n.j.cox@durham.ac.uk
>>>
>>> Thomas Speidel
>>>
>>> Following up on my previous post:
>>> http://www.stata.com/statalist/archive/2010-06/msg00984.html
>>> here is an example for something I am trying to achieve in a
>>> nice/efficient/eleganty way.
>>>
>>> I have a number of dummies: a, b, c, d, e (missing values do exist)
>>> Disease=true if the following conditions are met:
>>>
>>> 1) a must be true AND
>>> 2) any two of b, c, d, e are true
>>>
>>> As I said missing values are crucial, especially when evaluating the
>>> second condition.
>>>
>>> My current program works, but I don't think it is efficient and it
>>> probably does things that are unnecessary:
>>>
>>> *******************************************
>>> egen anytwo = rowtotal(a b c d e), missing
>>> egen missing = rowmiss(a b c d e)
>>> replace anytwo = . if (anytwo==0 & missing>=2 & missing<.)
>>> replace anytwo = . if (anytwo==1 & missing==1)
>>> replace anytwo = . if (anytwo==1 & missing==3)
>>> replace anytwo = . if (missing>=4)
>>>
>>> gen disease = 1 if (a==1 & anytwo>=2 & anytwo<.)
>>> replace disease = 0 if (a==1 & anytwo<2)
>>> replace disease = 0 if a==0
>>> replace disease =. if a==.
>>> *******************************************
>>>
>>> I tried to play around with cond, but I found it was making this much
>>> more complicated then it is.  I know I am complicating my life more
>>> than I need to which is why I am looking for alternative solutions.
>>>
>>> *
>>> *   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/
>>>
>>
>>
>>
>> --
>> Thomas Speidel
>>
>>
>> *
>> *   For searches and help try:
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>> *   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/
>>
>
>
>
> -- 
> Thomas Speidel
>
>
> *
> *   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/
>



-- 
Thomas Speidel


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