Assume that there are k expert measuring some quality x with a number between zero and one, $x_i \in [0,1], i=1,2,...,k$. I would like to first know the aggregated quality of x with respect to the experts' opinions, and then I also want to know the extent to which the experts agree (or disagree).
To do so, I used the following model where x is the latent quality (similar to Kruschke, Chapter 9, Equation 9.4):
$ x_i \sim beta(x(k-2)+1,x(k-2)+1)$
where x is the mode of the beta, and $k>0$ is a constant. I know that the bigger value for $k$ means the more agreement between experts. But it does not show to what extent they agree.