Chapter 5

If you have no data at all, use the worksheet in section 5.1, which projects a variety of assumed growth patterns into the future. When data develop, use the models in sections 5.2-5.5 to fit growth curves or functions of time using ordinary-least-squares regression. The linear growth model (Section 5.2) predicts a constant amount of growth each time period, while the exponential (Section 5.3) predicts constant percentage growth. In both linear and exponential growth, the forecasts are unbounded. In the modified exponential (Section 5.4) and logistic (Section 5.5) models, the amount of growth declines each period, so the forecasts are bounded by a saturation level.