Note on Discordant Observations
John A. Hartigan · Journal of the Royal Statistical Society Series B (Statistical Methodology) · 1968
Summary Given a set of observations x1, …, x n, a Bayes measure of discordance of an observation x is defined to be the distance between the posterior distributions of a parameter, in the presence or absence of x. A measure of dissimilarity between two observations is also proposed. For large numbers of observations, these two measures may be approximated by simple functions of the log likelihood, thereby avoiding dependence on prior distributions. The theory is applied to data in which 13 judges ranked 20 mothers; each judge is supposed to give an independent observation on the mothers, with the analysis showing which judges are discordant from the rest and which judges are similar to each other.