# Theta-logistic population growth model

Filed under:
Ecology

**This example is part of the NCEAS non-linear modelling project**

**Author: Casper W. Berg**

The example is a theta-logistic nonlinear state-space population model. The population size is modelled as a nonlinear function of its previous size, with a discrete-time theta-logistic process model: N(t+1)=theta-logistic(N(t)) plus a normally distributed process error, and the observation error is also normally distributed. This example uses simulated data from the same model to test it. More details are available in Pedersen et al. (2011).