[R-sig-ME] Using variance components of lmer for ICC computation in reliability study

[Pierre de Villemereuil]

Yes, but would an assumptions that thresholds are conserved between the groups you compare reasonable (depends on the "groups" of course)? In that case (with "fixed" thresholds assumptions), you might be able to start talking about the variance, no?

Of course, it's still non identifiable, in the sense that you need to assume fixed thresholds to talk about this. I figured it was the assumption David was making.

Cheers,
Pierre.

Le mardi 19 juin 2018, 10:04:22 CEST Jarrod Hadfield a écrit :
> Hi,
> 
> No - the residual variance is non-identifiable in a threshold model 
> irrespective of the number of thresholds unless the thresholds are 
> constrained in some way (e.g. fully constrained as in the paper I 
> previously referenced). Strong depletion from the central category would 
> simply mean the two thresholds are close together.
> 
> Cheers,
> 
> Jarrod
> 
> 
> On 19/06/2018 08:38, Pierre de Villemereuil wrote:
> > Hi,
> >
> >> Maybe there is information about the residual variances in the 2-threshold model in such a setup?
> > Maybe, but it would be quite hard (if possible at all) to distinguish from changes in the mean, wouldn't it? Unless the changes in the "spreading" are quite dramatic and located in the extreme categories with a strong "depletion" from the central one.
> >
> > It's interesting to think about it though.
> >
> > Cheers,
> > Pierre.
> >
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> 
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