Statalist


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

RE: st: clogit data format


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: clogit data format
Date   Thu, 20 Mar 2008 17:23:54 -0000

If I understand this correctly, individuals for whom all raters agree
cannot 
be included in a -clogit- analysis. That seems to rule it out absolutely

as a way of examining the structure of agreement and disagreement. 

There are many ways to look at the data, depending on what data
generation process
you have in mind.  It's not clear to me that a binary  
response inescapably implies a logit analysis. Missings aside, four
ratings
for each individual imply that your data can be collapsed with loss of 
information to a table of the frequencies of 16 joint outcomes: 

0000
0001
0010
0011
...
1111 

which may allow structure to be discerned. Here "0000" means all four
raters
assign "0", and so forth. 

Nick
n.j.cox@durham.ac.uk 

Margaret R Grove

To clarify further where I think the problem may lie:

PHREG output notes "Number of Observations Read   2300" and "Number of 
Observations Used  2000" (300 have missing values for the dependent 
variable)

CLOGIT notes that 1710 observations (496 groups) were dropped because of

all negative or all positive outcomes and our final number of 
observations is 290!

With this I wonder if comparing the two methods makes sense and which 
method (PHREG or CLOGIT) is preferable (if any)?


*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   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