\(U =\) Ultimate Loss
\(R =\) Estimate of Unpaid losses
\(U_0 =\) a priori estimate of Ultimate Losses
\(p_k =\) % of total losses paid at \(k\)
\(q_k = 1 - p_k =\) % of total losses unpaid a \(k\)
\(C_k =\) Actual paid losses at \(k\)