The standard approach to estimating median voter expenditure equations has incorporated the specification of a congestion function, a(N), to convert the total output (Q) of a government provided good into individual consumption (qi). In their classic papers, Borcherding and Deacon [2] and Bergstrom and Goodman [1] adopted a simple form, a (N) = N-Y. Using this form, estimated values of y = 0 imply that the service in question is classified as a pure public good, while y = 1 implies a private good. This approach is attractive from an empirical standpoint because it allows the data to determine the degree of publicness of the local government output. The empirical findings of Borcherding and Deacon, Bergstrom and Goodman, and numerous later studies that used the median voter approach,' indicate that most local government services do not exhibit a significant degree of publicness.2 Recent studies have questioned whether estimates of publicness are sensitive to the particular specification of the congestion relationship [6; 9]. Researchers also have objected to the standard form because it holds the degree of publicness fixed, which implies a decreasing marginal rate of congestion [3; 6; 15]. Moreover, holding the degree of publicness fixed implies a single estimated value of y is sufficient to classify the publicness of the good. Critics of the standard approach argue that the degree of publicness should vary with population size. For instance, a local park may exhibit no congestion for small population sizes, but eventually become congested as population increases. Unfortunately, no clear guidelines for specifying the congestion function are available. Edwards suggested that flexible functional forms are to be preferred because they let the data speak for themselves [6, 92]. He also argued that the preferred form is one that fits the data best. Based on these criteria, he concluded that a flexible form, such as an exponential form, is su-