Growth Curve Modeling - 9781118764046

Issues concerning national economic growth, human population growth, agricultural/forest growth, the growth of firms as well as of various insect, bird, and fish species routinely capture our attention. But how is such growth modeled and measured? This book addresses how to monitor the change in variables over time since there is no “one size fits all” approach to growth measurement. For example, a growth model useful for studying an agricultural crop will most assuredly not be appropriate for fishery management, and if, for instance, one is interested in calculating a growth rate for a time series data set, a decision has to be made as to whether or not one needs to determine a relative rate of growth, an average annual growth rate, an ordinary least squares growth rate, a geometric mean growth rate, etc. Moreover, the choice of a growth rate is subject to the idiosyncrasies of the data set itself, i.e is the data series trended, is it stationary, and is it presented on an annual, quarterly, or monthly basis? Also, whether the appropriate growth curve should be linear or sigmoidal (S-shaped) with an upper asymptote should be questioned. The aforementioned issues concerning the selection of a growth modeling methodology are of profound importance to those looking to develop sound growth measurement techniques. This book attempts to point readers in the appropriate direction to properly model and analyze their data. While derivations of virtually all of the major growth curves/models have been provided, they have been placed into end-of-chapter appendices so as not to interrupt the general flow of the material. In addition to detailed discussions of growth modeling/theory, the requisite mathematical and statistical apparatus needed to study the same is provided, and SAS® code is given so that readers can estimate their own specialized growth rates and curves.