Groeianalyses

Groeianalyses refers to a set of statistical and mathematical methods used to study how quantities grow over time. The term appears in Dutch-language literature and covers analyses of biological growth (organisms, tissues, crops), somatic growth in medical contexts, and, more broadly, any time-series describing increases in size, mass, output, or performance. The primary aims are to describe growth trajectories, estimate growth rates, compare growth between groups or treatments, and forecast future size or yield.

Analytical approaches include parametric growth curves such as the logistic, Gompertz, von Bertalanffy, and Richards models, which describe how the measured variable changes with age or time. Nonparametric methods, including smoothing and spline fits, can capture flexible shapes without assuming a fixed form. Estimation is typically performed with nonlinear regression or maximum likelihood; Bayesian methods are also used to incorporate prior information and quantify uncertainty.

Applications span plant and animal science, where growth curves guide nutrition, breeding, and harvest planning; ecology and epidemiology, to describe population or disease progression; and economics or market research, where growth analyses can model adoption curves or output growth over time. Comparative growth analyses often focus on differences in asymptotic size, growth rate, or age at inflection.

Challenges include choosing an appropriate model, handling irregular or missing measurements, and accounting for individual variability and developmental stages. Data quality, measurement error, and scale differences can affect parameter estimates. Reporting standards typically emphasize parameter estimates with confidence intervals or credible intervals, goodness-of-fit metrics, and plots of observed versus fitted trajectories.