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st: reliability with -icc- and -estat icc-
From
Lenny Lesser <[email protected]>
To
statalist <[email protected]>
Subject
st: reliability with -icc- and -estat icc-
Date
Mon, 25 Feb 2013 20:56:52 -0800
I have 4 raters that gave a score of 0-100 on 11 smartphone applications.
The data is skewed right, as they all got low scores. I'm using the
ranks (within an individual) instead of the actual scores. I want to
know the correlation in ranking between the different raters.
I've tried the two commands:
-xtmixed rank Application || Rater: , reml
-estat icc
(icc=0.19)
and
-icc rank Rater Application, mixed consistency
(icc=0.34)
They give me two different answers. Which one is correct?
Next, we found out that rater 4 was off the charts, and we want to
eliminate her and rerun the analysis. When we do this we get wacky
ICCs. In the first method we get an ICC of 2e-26. In the 2nd method
(-icc), we get -.06. Eliminating any of the other raters gives us
ICCs close to the original ICC. Why are we getting such a crazy
number when we eliminate this 4th rater?
I'm guessing this might be instability in the model, but I'm not sure
how to get around it.
Lenny
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