TY - JOUR A1 - Schmertmann, Carl T1 - A system of model fertility schedules with graphically intuitive parameters Y1 - 2003/10/10 JF - Demographic Research JO - Demographic Research SN - 1435-9871 SP - 81 EP - 110 DO - 10.4054/DemRes.2003.9.5 VL - 9 IS - 5 UR - https://www.demographic-research.org/volumes/vol9/5/ L1 - https://www.demographic-research.org/volumes/vol9/5/9-5.pdf L2 - https://www.demographic-research.org/volumes/vol9/5/9-5.pdf L3 - https://www.demographic-research.org/volumes/vol9/5/files/All%20Files%20(zip).zip L3 - https://www.demographic-research.org/volumes/vol9/5/files/FILE%20I%20QS%20Model.xls L3 - https://www.demographic-research.org/volumes/vol9/5/files/FILE%20II%20CT%20and%20QS%20fits%20to%20international%20schedules.pdf L3 - https://www.demographic-research.org/volumes/vol9/5/files/FILE%20III%20CT%20and%20QS%20fits%20to%20international%20schedules.xls L3 - https://www.demographic-research.org/volumes/vol9/5/files/FILE%20IV%20QS%20fits%20to%20Swedish%20time%20series.xls N2 - I propose and examine a new family of models for age-specific fertility schedules, in which three index ages determine the schedule's shape. The new system is based on constrained quadratic splines. It has easily interpretable parameters, is flexible enough to fit a variety of "noiseless" schedules well, and is inflexible enough to avoid implausible estimates from noisy data. Across a set of over two hundred contemporary ASFR schedules, the new model fits a majority better, and in some cases much better, than the Coale-Trussell model. When fit to a recent Swedish time series, model parameters exhibit simple, regular changes over time, suggesting utility in forecasting applications. In simulated small-sample data the new model produces plausible ASFR estimates, with errors similar to Coale-Trussell. ER -