The Stata Journal
180 From the help desk Thus, the log likelihood can be written lnL =ln i∈Ω0 e−exiβ1 i∈Ω1 1−e−exiβ1 i∈Ω1 eyixiβ2 (eexiβ2 −1)y i! = i∈Ω0 −exiβ1 + i∈Ω1 ln(1−e−exiβ1) + i∈Ω1 yixiβ2 − i∈Ω1 ln(eexiβ2 −1)− i∈Ω1 ln(yi!) =ln{L 1(β )}+ln{L2(β2)}...