Forum: open-discussion

BTYD package [ Reply ]
By: laura barrigon on 2013-07-11 08:40

Hi,
I am building a CLV model using the Buy til you die (BTYD) package
But I can't use it for the whole period of calibration that I want (which is one year).
It does all right the CBS matrix, but it has troubles with the parameter estimation, saying:
Error in optim(logparams, pnbd.eLL, cal.cbs = cal.cbs, max.param.value = max.param.value, : L-BFGS-B needs finite values of 'fn'

I've found out that it has no troubles at all when the calibration period is shorter(8 mounths and 20 days). I've read in a master thesis that the pareto/nbd model has limitations on the lenght of the period of analysis.
I have not read such a thing in BTYD instructions or in the paper "Counting Your Customers: Who Are They and What Will They Do Next? Schmittlein, David C;Morrison, Donald G;Colombo, Richard" where the model was build.

Do you know anything about it?