A variation of this approach is based on an informal of the principal customers of the company. Under this approach, sales are estimated on the basis of reports prepared by special company representatives who contact customers for the primary purpose of evaluating their future needs. From the sales forecasts available, and the information gathered by the special representatives and interpreted through their personal observation and judgments, an initial sales estimate for each geographical sales division(or product) is developed These estimates are then adjusted to take into account basic information that the higher sales managers have about such factors as expected economic conditions, population trends, purchasing power, and other conditions that may affect the market. In addition, consideration should be given to sales of the last year or two and to stock holdover on the part of customer outlets. This method is useful in situations where the number of customers is limited.