MackChainLadder: `tail = FALSE` works fine, `tail = TRUE` errors. about chainladder

[mages]

The issue arises as the development factors don't show any tail behaviour:

tail_false$f
 [1] 1.9307165 1.1809163 1.0857623 1.0266246 1.0170353 1.0185534 1.0041805
 [8] 1.0023209 1.0006539 0.9997043 1.0006834 1.0000000 1.0000000

With tail=TRUE MackChainLadder attempts an extrapolation using log(f - 1), which fails when the development factor are 1 already. See https://mages.github.io/ChainLadder/articles/ChainLadder.html#basic-idea for more details.

[kennedymwavu]

Thank you so much for the explanation!