In a typical game examining voluntary contribution to the provision of
step-level public goods, each member of a group of size n receives an
endowment and then decides privately and anonymously how much of it t
o contribute for the provision of the good. The good is provided to al
l group members if and only if their total contribution is equal to, o
r larger than some threshold. While previous research assumed that gro
up members have complete information about the threshold, the present
article relaxes this assumption by treating the threshold as a random
variable with a commonly known distribution. Three models, a subjectiv
e expected value model, a cooperative model and a strategic model are
proposed to account for the individual's contribution decision. Genera
l solutions are then derived and their predictions for the case of a u
niformly distributed threshold are evaluated.