Statistics
Explore statistical methods, their assumptions, interpretation and limitations.
Research field
Method family
Age-Period-Cohort Model
The age-period-cohort (APC) model decomposes variation in a vital rate — mortality, incidence, fertility — into three temporal dimensions: the age of individuals, the calendar period of observation, and the birth cohort to which they belong...
Amino Acid Racemization
Amino acid racemization (AAR) dating estimates the age of biogenic materials such as mollusc shell, ostrich eggshell, bone, and teeth from the slow chemical conversion of amino acids from one mirror-image form to the other after an organism...
Argon-Argon Dating
Argon-argon (40Ar/39Ar) dating is the modern, high-precision successor to conventional potassium-argon dating, in which the parent potassium is measured indirectly by converting it to a measurable argon isotope inside a nuclear reactor. A p...
Bayesian Chronological Modeling
Bayesian chronological modeling refines archaeological chronologies by combining the calibrated probability distributions of individual radiocarbon dates with prior archaeological knowledge — most importantly the stratigraphic order of samp...
Brass Relational Logit Model
The Brass relational logit model is a two-parameter system for representing and smoothing a life table by relating it to a chosen standard. Introduced by William Brass in 1971, it transforms the survivorship function with a logit and posits...
Coale-Demeny Model Life Tables
The Coale-Demeny regional model life tables are a system of standard age patterns of mortality, distilled from hundreds of empirical life tables into four regional families — North, South, East, and West — each indexed by a mortality level....
Coale-McNeil Marriage Model
The Coale-McNeil model is a parametric description of how first marriages are distributed by age. Ansley Coale and Donald McNeil showed in 1972 that the age pattern of first marriage in widely different populations has a common shape, captu...
Coale-Trussell Model
The Coale-Trussell model is a two-parameter parametric description of the age pattern of marital fertility, introduced by Ansley Coale and James Trussell in 1974. It expresses observed age-specific marital fertility as a standard natural-fe...
Gompertz-Makeham Law of Mortality
The Gompertz-Makeham law is the foundational parametric model of adult human mortality. Benjamin Gompertz showed in 1825 that the force of mortality rises exponentially with age, and William Makeham added an age-independent background term...
Healthy Life Expectancy
Healthy life expectancy partitions ordinary life expectancy into the years a person can expect to live in good health and the years expected to be lived with disability or ill health. Building on the life table, the classic Sullivan method...
Heligman-Pollard Model
The Heligman-Pollard model is an eight-parameter parametric law that describes the age pattern of mortality across the entire human lifespan in a single equation. Introduced by Larry Heligman and John Pollard in 1980, it represents the odds...
Lee-Carter Model
The Lee-Carter model is a stochastic framework for modeling and forecasting age-specific mortality rates, introduced by Ronald Lee and Lawrence Carter in their landmark 1992 paper. It decomposes the logarithm of age-specific death rates int...
Lee-Carter Mortality Model
The Lee-Carter model is the benchmark method for forecasting human mortality. Introduced by Ronald Lee and Lawrence Carter in 1992 for U.S. data, it captures the entire schedule of age-specific death rates with a remarkably parsimonious str...
Life Table
A life table is a systematic, age-structured summary of the mortality experience of a population. It traces a hypothetical cohort of births — conventionally 100,000 — through successive age intervals, recording how many survive, how many di...
Migration Models
Migration models are quantitative frameworks for explaining and forecasting population movement between geographic units. Lee's (1966) push-pull theory classifies factors at origin and destination into positive and negative forces, modulate...
Multistate Life Table
The multistate life table, also called the increment-decrement life table, generalizes the ordinary life table to populations that move among several living states — such as healthy and disabled, married and unmarried, or employed and unemp...
Potassium-Argon Dating
Potassium-argon (K-Ar) dating is a radiometric technique that determines the age of volcanic rocks and minerals from the slow radioactive decay of potassium-40 to argon-40. Potassium is abundant in many rock-forming minerals, and a fixed fr...
Relational Gompertz Fertility Model
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...
Siler Mortality Model
The Siler model is a parametric description of the entire age pattern of mortality, from birth to extreme old age, built as the sum of three competing hazards: a high but rapidly declining risk in early life, a roughly constant background r...
Stable Population Theory
Stable Population Theory is a mathematical framework in demography that describes the age structure and growth dynamics of a closed population subject to constant age-specific fertility and mortality schedules over a long period. Foundation...
Sullivan Method
The Sullivan method is a simple, widely used technique for estimating health expectancy — the average number of years a person can expect to live in a given health state, such as free of disability. Introduced by Daniel Sullivan in 1971, it...