Marketing research has to develop as a dynamic process if it is to fulfil its major purpose of helping management reach better decisions more quickly. Innovation is disruptive and change demands that researchers provide continuous and up-to-date signals of its pace and its direction. Unstable conditions are those which require most of management decision-making but in these situations the commercial purchase and prescription audits are often divergent and always too late. We found that key components in building a simple, iterative model were a few salient questions related to reasons for product choice. When these were incorporated into the model, it then produced good forecasts even in volatile states and with minimal data. An essential feature of the model is a prescription share index and the mechanism by which this and other variables are put together to provide management with a practical tool of promotional significance is explained.