Richard Hydomako

The Modified Beta-Geometric model might be what you're looking for: https://github.com/CamDavidsonPilon/lifetimes/blob/master/lifetimes/fitters/modified_beta_geo_fitter.py Some model details, as they relate to P(alive) for customer who have only made one purchase: http://www.brucehardie.com/notes/021/palive_for_BGNBD.pdf