BI-LOGISTIC GROWTH

The S-shaped logistic growth model has been extensively studied and ap plied to a wide range of biological and socio-technical systems. A mod el, the Bi-logistic, is presented for the analysis of systems that exp erience two phases of logistic growth, either overlapping or sequentia lly. A nonlinear least-squares algorithm is described that provides Bi -logistic parameter estimates from time-series growth data. Model sens itivity and robustness are discussed in relation to error structure in the data. A taxonomy and some examples of systems that exhibit Bi-log istic growth are presented. The Bi-logistic model is shown to be super ior to the simple logistic model for representing many growth processe s.