Any one of a number of functional forms (such as the logistic curve) that starts out slowly but at an increasing rate, but then the rate slows as it approaches an asymptote (see saturation level). Such curves can be used to capture a diffusion process, as described in Meade and Islam (2001).
- Meade, N. & T. Islam (2001), “Forecasting the
diffusion of innovations: Implications for time-series extrapolation,” in J. S.
Armstrong (ed.),
*Principles of Forecasting*. Norwell, MA: Kluwer Academic
Press.