Estimation of loss reserves with lognormal development factors

This paper uses a development technique to estimate the loss reserve in a classical run-off triangle setting. Closed-form solutions for unbiased estimates of reserves and their corresponding standard errors can be obtained by assuming lognormal distributions of the development factors. The technique is applied to the Bornhuetter–Ferguson method [Bornhuetter, R.L., Ferguson, R.E., 1972. The actuary and IBNR. Proc. Casualty Actuarial Soc. 59, 181–195] and to two previously studied data sets.