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st: RE: limitations of "generate" with missing data
From
"Fernando Rios Avila" <[email protected]>
To
<[email protected]>
Subject
st: RE: limitations of "generate" with missing data
Date
Mon, 11 Apr 2011 18:09:19 -0400
Hi Michael,
The limitation is not with generate. But rather with the way u are creating
your dummy variable
I think this should do the trick
set obs 1000
gen r=runiform()
replace r=. if runiform()>.5
gen r2=r>0.7 if r1!=.
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Michael Costello
Sent: Monday, April 11, 2011 6:01 PM
To: statalist
Subject: st: limitations of "generate" with missing data
Statalisters,
I recently ran into a problem with the following dataset:
. tab gread_comp_score_pcnt, m
gread_comp_ |
score_pcnt | Freq. Percent Cum.
------------+-----------------------------------
0 | 150 7.50 7.50
.2 | 85 4.25 11.75
.4 | 97 4.85 16.60
.6 | 82 4.10 20.70
.8 | 72 3.60 24.30
1 | 15 0.75 25.05
. | 1,499 74.95 100.00
------------+-----------------------------------
Total | 2,000 100.00
The high number of "missing" is by design, a by-product of a horizontally
structured dataset that I have yet to rectify.
When I run the command:
gen gread_comp_score_pcnt80= (gread_comp_score_pcnt>.79) I am left with
. tab gread_comp_score_pcnt80, m
gread_comp_ |
score_pcnt8 |
0 | Freq. Percent Cum.
------------+-----------------------------------
0 | 414 20.70 20.70
1 | 1,586 79.30 100.00
------------+-----------------------------------
Total | 2,000 100.00
As you can see, the 87 values above .79 were set to 1, but so were all the
missing values!! I have toyed with the code a bit, trying variations such
as . gen gread_comp_score_pcnt80= (gread_comp_score_pcnt>.79 &
gread_comp_score_pcnt!=.)
but that converts all the missing to 0's, which is only marginally better.
So the question is, is there some way to use a single, precise line of code
to create eighty-seven 1's, four hundred fourteen 0's and 1499 Missing
values in one dummy variable? I know I can do it with several lines of
code, but I'm looking for something more concise, as it needs to run many
hundreds of times.
Thanks for your help,
-Michael
--
Michael Costello
MS Candidate, Statistics 2011
202-246-1627
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