Confronta i metodi

	Relational Gompertz Fertility Model	Brass P/F Ratio Method
Campo	Demografia	Demografia
Famiglia	Regression model	Process / pipeline
Anno di origine	1984	1964
Ideatore	William Brass; standard refined by Heather Booth	William Brass
Tipo	Relational parametric model of the cumulative fertility schedule	Indirect fertility estimation adjusting period rates using reported parities
Fonte seminale	Booth, H. (1984). Transforming Gompertz's function for fertility analysis: The development of a standard for the relational Gompertz function. Population Studies, 38(3), 495–506.	Brass, W. (1975). Methods for Estimating Fertility and Mortality from Limited and Defective Data. Carolina Population Center, University of North Carolina at Chapel Hill.
Alias	Brass Relational Gompertz Model, Gompertz Relational Fertility Model, Relational Gompertz Function	P/F Ratio Method, Brass P/F Ratio Technique, Parity/Fertility Ratio Method
Correlati	4	4
Sintesi	The relational Gompertz model expresses any population's cumulative fertility schedule as a simple linear transformation of a fixed standard schedule, after both are mapped through a double-logarithm (gompit) transform. Developed by William Brass and given its widely used standard by Heather Booth, it characterizes the entire age pattern of fertility with just two parameters — α, which shifts the schedule earlier or later, and β, which controls how concentrated or spread out childbearing is. This makes it a robust tool for smoothing, fitting, and especially for correcting and estimating fertility from the limited and error-prone data common in developing countries.	The Brass P/F ratio method is the foundational technique of indirect fertility estimation, designed to correct fertility levels in populations whose vital registration is incomplete but where a census or survey reports both recent births and lifetime children ever born. It compares F — the period fertility a synthetic cohort would have accumulated by each age — with P, the average parity (children ever born) actually reported by women of that age. The ratio of the two diagnoses and corrects errors in the reported level of current fertility, yielding an adjusted total fertility rate from data too defective for direct calculation.