Hi,
I am trying to an analysis of agreement between two raters (dichotomous
variables) using kappci.
Each set of data is 14 pairs of Y/N.
I'm confused by the behaviour of kappci - sometimes it produces a result
that looks fine, sometimes it produces a result but the kappa value
seems way too low. Other times it fails with an odd error message.
Here's an example of the error:
var1 var2 var3
1 y y
2 y y
3 n y
4 y y
5 y y
6 y y
7 y y
8 y y
9 y y
10 n y
11 y y
12 y y
13 y y
14 y y
. kappci var2 var3, pos("y")
'.' found where number expected
r(7);
I have re-entered the data manually but with no luck.
With a different set of data:
var1 var2 var3
1 y y
2 n y
3 y y
4 y y
5 y y
6 y y
7 y y
8 y y
9 y y
10 y y
11 y y
12 . .
13 y y
14 y y
. kappci var2 var3,pos("y")
Expected Observed -- Binomial Exact --
Agreement Agreement [95% Conf. Interval]
--------------------------------------------
80.61% 92.86% 66.13% 99.82%
Kappa [95% Conf. Interval] Z Prob>Z
-------------------------------------------------
0.6316 0.0418 0.9325 2.54 0.0055
Any ideas would be gratefully received - I've been going round in
circles and getting nowhere fast for the last few hours.
Thanks in advance,
Nigel
--
Nigel R. Armfield. MSc, MIEEE, MIET.
Senior Research Assistant (Telepaediatrics)
Centre for Online Health
The University of Queensland
Level 3, Royal Children's Hospital
Herston 4029
Australia
*
* 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/
