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Re: st: _rmcoll issues
From
Richard Williams <[email protected]>
To
[email protected], "[email protected]" <[email protected]>
Subject
Re: st: _rmcoll issues
Date
Tue, 10 Dec 2013 22:39:47 -0500
At 05:31 PM 12/10/2013, Stas Kolenikov wrote:
I have the following cross-tab of two variables:
. tab pd2usmex years_in_us
PD2. What |
country |
were you | years_in_us
born in? | 1 2 3 4 | Total
-----------+--------------------------------------------+----------
1 | 240 0 0 0 | 240
2 | 0 103 451 378 | 932
9 | 0 33 99 123 | 255
-----------+--------------------------------------------+----------
Total | 240 136 550 501 | 1,427
For whatever reason, _rmcoll senses that something is fishy between
the two variables, but decides to drop the last category of the second
variable, rather than the first one on which these two variables
logically overlap.
. _rmcoll ib1.pd2usmex ib1.years_in_us
note: 4.years_in_us omitted because of collinearity
I think this is a bit odd.
I think it just goes with the highest code. Try running this (drop
the fws if you don't need them):
preserve
recode years_in_us (3 = 5)
_rmcoll ib1.pd2usmex ib1.years_in_us [fw = freq]
recode years_in_us (2 = 6)
_rmcoll ib1.pd2usmex ib1.years_in_us [fw = freq]
restore
preserve
recode years_in_us (1 = 5)
recode years_in_us (2 = 1)
_rmcoll ib1.pd2usmex ib1.years_in_us [fw = freq]
restore
The highest value always gets dropped.
-- Stas Kolenikov, PhD, PStat (ASA, SSC)
-- Senior Survey Statistician, Abt SRBI
-- Opinions stated in this email are mine only, and do not reflect the
position of my employer
-- http://stas.kolenikov.name
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-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
HOME: (574)289-5227
EMAIL: [email protected]
WWW: http://www.nd.edu/~rwilliam
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