Benktander method

Benktander, 1976, then Hovinen, 1981, working independently: take the ultimate produced by Bornhuetter-Ferguson and reuse it as the a priori loss ratio in a second pass. Chain ladder trusts the triangle entirely, Bornhuetter-Ferguson trusts the a priori entirely for the undeveloped share, and Benktander goes one step further. Algebraically the result is a weighted average of chain ladder and Bornhuetter-Ferguson whose weight is the percent developed itself. The more mature the year, the closer the method sits to chain ladder, which is the behavior you want. The estimator has a lower mean squared error than the other two across most realistic settings, hence its use as a default when you are torn between them. It keeps the same blind spot, though: if the development pattern is wrong, all three methods are wrong together and in the same direction.