Cobb-Douglas functional forms: A particular mathematical form of a production function of an economic producing unit; i.e. of the relationship between the level of production Q and the amounts of inputs or factors of production - capital K and labor L. A simple Cobb-Douglas funtion is given by:

where, A, a, and b are econometrically estimated constants. Coefficients a and b have particular relationships which reflect whether the returns to scale of production are constant, increasing or decreasing. If the sum of a and b is constant, this means the production function reflects constant returns to scale; i.e. if all inputs are expanded in the same proportion, output expands in the same proportion.