On the Quantum of Fertility: A Bias Correction Approach Using the Slope Information

P. C. Roger Cheng, National Central University, Taiwan

Given the fact that a satisfactory estimate of cohort fertility depends crucially on an accurate prediction of the future trend of period quantum, this paper shows that one can utilize available fertility data to disclose some useful information about that trend so as to effectively correct the prediction bias occuring under the no-quantum-change anticipation. Specifically, we extract clues about both the slope and the change of slope in current quantum movements, and then exhibit a very high correlation between the slope of period quantum and the prediction bias which comes from a large number of experiments by fully utilizing the existing data from Canada, the U.S., and 23 European countries, As a result, the prediction bias can be significantly corrected based on this relationship so that a satisfactory estimate of cohort fertility is thus obtained.