[1] The resulting costs of the input factors are allocated to the individual products according to a weighting key, the so-called equivalence numbers.
An airline can determine the cost of the transportation service by dividing air freight and passengers by weight.
In the cogeneration plants, the Carnot method allocates the fuel to the products useful heat and electrical work.
Criticism of the equivalence number method is justified by the fact that completely arbitrary and random keys can be chosen.
a1 and a2 are the allocation factors for the respective output, i.e. they describe the proportion of the input that is assigned to a co-product.