Tweedie distributions for fitting semicontinuous health care utilization   cost data
  We explore a statistical distribution that can simultaneously model the probability of zero outcome for non-users of health care utilization and continuous costs for users. We compare this distribution to other com- monly used models on example data and show that it fits cost data well and has some appealing properties that provide flexible use. 
Christoph Kurz
stat.AP q-bio.QM