ABSTRACT
Some characteristics of drug products result in uncertain and unpredictable de mand patterns. In many cases, historic sales can be a good indicator of future de mand; however, this is probably less so in the pharmaceutical industry, where no strong basis exists for estimating the number of people who will require a partic ular treatment in a specific future time period. This is compounded by the normal uncertainties associated with forecasting, including the perceptions of buyers (e.g., prescribing doctors) relative to competitive products, or the introduction of "next generation" products. The availability of generically equivalent competitive products means that product unavailability, in many cases, results in a lost sale versus merely a deferred shipment. Customers generally need the product im mediately and cannot wait even a few days for their prescriptions to be filled.
