st: RE: combining reliability trial data

[Nick Cox <n.j.cox@durham.ac.uk>]

The error in using -bagroup- arises, I guess, because it lacks a -version- statement. Inserting a line such as 

version 7

after each -program- statement is likely to fix the problem that braces are used within the program in ways that clash with present rules. I have not tested this guess and there may be other problems. 

See also [P] version for details here. 

-bagroup- comes from the following place. Please remember that you are asked to explain _where_ user-written programs you refer to come from. 

STB-55  sbe33 . . . . Comparing several methods of measuring the same quantity
        (help baplot, bagroup, bamat, sdpair if installed)  . . . . .  P. Seed
        5/00    pp.2--9; STB Reprints Vol 10, pp.73--82
        commands implementing the Bland-Altman approach to comparing
        two or more measurement methods;  also alternative command to
        sdtest based on Pitman's method giving confidence intervals
        for variance ratios of paired data

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

Hilary Taylor

I am hoping to test the inter- and intra-rater variance of a measurement 
method.  I had two raters (R1 and R2) perform measurements on 28 items and 
each rater measured the set twice (t1 and t2).  The measurements are scale.

I have drawn up some Bland & Altman plots and have performed Pitman's 
tests.  I have carried this out for inter-rater (R1t1 vs R2t1) and 
intra-rater (R1t1 vs R1t2), however I would really like to combine the data 
somehow to make use of it all.  I thought the command 'bagroup' (Paul Seed, 
2000) might be useful but have been unable to explore this because the 
following error comes up:

bagroup  t1_r1  t2_r1  t1_r2  t2_r2
program error:  matching close brace not found

I would be grateful if you could tell me firstly, if this would be a useful 
thing to do (if I can get it working) and secondly, if you have any 
suggestions for a better way for me to combine these data (I would like to 
create plots and associated stats)?

(I am using Stata/SE 11.2)


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