Product Population Under the influence of effective marketing, the market population P of a given product starts off small and grows to a maximum in the manner shown by the following curve.

This curve is generated by the Standard Logistic Difference Equation shown below the curve. It gives the market's total product population today (P_new) in terms of the market's total product population yesterday (P_old). P is expressed as a fraction of the total possible population of the product within the market. That is, the maximum number of copies of the product which will ever be in the possession of customers. The k factor is a measure of the power and effectiveness of the enterprise's combined marketing, production and distribution processes.

The curve rises slowly at first because although potential demand from the 'empty' market is high, the product is not yet widely known. But as the marketing process takes effect and production gets going, the rate of consumption of the product by customers accelerates, so the curve becomes ever steeper. It remains at its maximum steepness during the period when everyone who wants the product is scrambling to buy one. Finally when most people who want one have one, consumption rapidly falls back to zero. The curve therefore flattens out and remains flat. The market is now what is termed 'saturated' with this product.