A new parametric model for fitting fertility curves.

What is the optimum way of describing the age-specific fertility pattern by mathematical functions? We propose a parametric fitting model, based on a mixture of Weibull functions, which performs well for countries where the fertility curve shows a non-traditional pattern. We also consider a simplified version of this model with a reduced number of parameters that can be applied to fit fertility curves in countries where the fertility pattern exhibits a classical shape. To test the new model, fertility curves for a range of countries and years are fitted empirically. The results show that both versions of the new model outperform existing procedures in most cases.