For example, the changes in the brand versus This report provides the tools required for a generic market shares due to the launch of complete analysis of the drivers of prescription generic products are expected to drive a decline drug expenditures by in the rate of growth in prescription drug expenditures. [...] The cross effect is distinct from the price and quantity effects and must be included if the decomposition is to fully account for the change in X. 2. The designation “Laspeyres” comes from the well-known the Laspeyres price index methodology. [...] In the quantity of drugs has increased only because of this case, the individual effects will be reported as the launch of a generic drug and the price discount it described in the next section (Section 4) and the offers. [...] In such a case, the generic 10 The Drivers of Prescription Drug Expenditures – A Methodological Report – December 2013 4. Formulas for Calculating the Drivers of Prescription Drug Expenditures This section provides the formulas for calculating the As a minimum, the following data elements are drivers of prescription drug expenditure, along with required for two time periods: the data requirements [...] Age information may be available in the form of age bands; the more granular the age information, the more precise the calculation for the aging effect.