Or should they rely on the elegant nonparametric approach that
appears so promising? It will be here argued that ecological forecasting based on parametric models
presents two key comparative advantages over nonparametric approaches. First, the likelihood of
parametric forecasting failure can bediagnosed thanks tosimple Bayesian model checking procedures.
Second, when parametric forecasting is diagnosed to be reliable, forecasting uncertainty can be
estimated on virtual data generated with the fitted to data parametric model. Incontrast, nonparametric
techniques provide forecasts with unknown reliability. This argumentation is illustrated with the simple
theta-logistic model that was previously used by Perretti and collaborators to make their point. It should
convince ecologists to stick to standard parametric approaches, until methods have been developed to
assess the reliability of nonparametric forecasting.