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

[Jarrod Hadfield]

Hi,

I think the residual variance is still non-identifiable with multiple 
thresholds. In fact,  this paper:

https://gsejournal.biomedcentral.com/track/pdf/10.1186/1297-9686-27-3-229

uses the non-identifiability in a 3 category problem to fix the 
thresholds but estimate the residual variance because this is the same 
as fixing the residual variance and estimating the free threshold.

Cheers,

Jarrod




On 18/06/2018 11:11, Pierre de Villemereuil wrote:
> Hi David,
>
>>> Thing is: there is nothing like this for GLMMs. The lowest level of "residual variance" is basically the
>>> distribution variance.
>>> You could think there would be such a thing with a threshold model, but it turns out that the total variance of
>>> the liability scale is non identifiable, so nothing there either.
>> There is some information when there are multiple thresholds.
> You mean information to measure e.g. additive over-dispersion?
>
> I agree but wouldn't you need quite a lot of thresholds (categories) for this to be measurable and not poses numerical issues? I have no practical experience in trying to account for that, so I'm curious if you have any experience in this.
>
> Best,
> Pierre.
>
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