1. In (4.17) a factor W is missing in the numerator of the expression in the middle.

2. The predictor of Xorns proposed in Paragraph 5B is not unbiased in general as a simple counterexample will show. The proposed reserve on an individual orns claim with past history T, U, V > υ′ = τ – T – U, {Y′(υ″); 0 ≤ υ″ ≤ υ′}, is

Suppose that Y = V and Y′(υ″) = Q(υ″/V)V, 0 ≤ υ″ ≤ V, where Q is a non-decreasing, deterministic function on [0,1] such that Q(0) = 0 and Q(1) = 1. In this case R = E[V∣T, U, V > Y′(υ′)] – Y′(υ′). If Q(s) > s for all s ∈ (0, 1), then Y′(υ′) = Q(υ′/V)V > υ′, hence