Its not optimal to think about this
as analogous to a fixed-effects ANOVA
with 2000 levels of the explanatory.
Rather, a random-effects model is the
better approach.  

The described application boils down 
to a nominal logistic regression variance 
components model.  Workplaces are random.  
The task is to model the nominal outcome 
with a random intercept term.  The estimated 
variance of the intercept, u_0, is the 
estimate of between-workplace variability.  
The withinn workplace variabilty, e_0, is 
likely to be derived under the assumption 
of equi-dispersion (binomially distributed 
errors) as pi**2/3.  This approach is 
possible using MIXNO a free software
program by Don Hedeker.

The ICC is then u_0/(u_0 + e_0)

Testing the assumption of equi-dispersion
for a random effects nominal logistic
regression model may be possible with MLwiN 
(commercial sotware), but I am not sure.  

HTH

Steve Gregorich





>The workplaces are randomly sampled. Selection of the individuals was based
>on a random sample design, but there are known biases.



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