A deterministic profit attribution model: The postal service, a case study

This paper derives a positive model relating changes in profitability to output levels, price, input quantities, and costs. The model involves decomposition of profit changes to define contributions associated with changes in the product market and production input variables. It can be derived from basic profit concepts without additional assumptions regarding the organization's behavioral decisions or about the shapes of the demand or production functions. It therefore avoids all normative underpinnings and is based strictly on measurable changes in the environment. The model is applied to results obtained from the United States Postal Service income statement. Changes in the Service's productivity and its components (e.g., labor, materials, and capital) are fully reconciled in an accounting sense with reported changes in net income. This reconciliation permits the identification of the sources of net income change.