Compare methods

	STIRPAT Model	Ecological Footprint Analysis
Field	Environmental Sociology	Environmental Sociology
Family	Regression model	Process / pipeline
Year of origin	1997	1996
Originator	Thomas Dietz & Eugene A. Rosa; Richard York	Mathis Wackernagel & William E. Rees
Type	Log-linear stochastic regression model of environmental impact drivers	Bioproductive-area accounting pipeline for human demand versus biocapacity
Seminal source	Dietz, T., & Rosa, E. A. (1997). Effects of population and affluence on CO2 emissions. Proceedings of the National Academy of Sciences, 94(1), 175-179.	Wackernagel, M., & Rees, W. E. (1996). Our Ecological Footprint: Reducing Human Impact on the Earth. New Society Publishers. ISBN: 9780865713123
Aliases	Stochastic IPAT, STIRPAT Regression, Stochastic Impacts by Regression on Population Affluence and Technology, Dietz-Rosa Impact Model	Ecological Footprint Accounting, Footprint-Biocapacity Accounting, Wackernagel-Rees Footprint, EF Analysis
Related	4	4
Summary	The STIRPAT model, short for Stochastic Impacts by Regression on Population, Affluence, and Technology, is a statistical reformulation of the IPAT identity that allows the drivers of environmental impact to be estimated and tested rather than merely asserted. Thomas Dietz and Eugene Rosa introduced it in 1997 to study national carbon dioxide emissions, recasting the deterministic accounting identity impact equals population times affluence times technology as a multiplicative stochastic model with an error term. Taking logarithms turns this into a linear regression whose coefficients are elasticities, the percentage change in impact associated with a one-percent change in each driver. This lets researchers ask whether impact rises strictly in proportion to population, as the original identity assumes, or whether there are increasing or decreasing returns to scale. Richard York, Rosa, and Dietz formalized and extended the approach in 2003, showing how additional drivers, quadratic terms, and panel structure can be incorporated within the same framework. STIRPAT has become the dominant quantitative tool in environmental sociology for analyzing the anthropogenic forces behind emissions, energy use, and ecological footprints.	Ecological footprint analysis measures human demand on nature by translating the resources a population consumes and the wastes it generates into the area of biologically productive land and sea required to supply them. Introduced by Mathis Wackernagel and William Rees in their 1996 book Our Ecological Footprint, the method expresses both demand (the footprint) and supply (biocapacity) in a common unit, the global hectare, so that the two can be compared directly. When a population's footprint exceeds the biocapacity available to it, the difference is an ecological deficit, and at the planetary scale a persistent deficit signals overshoot of the biosphere's regenerative capacity. The 2002 analysis by Wackernagel and colleagues operationalized this accounting at the global level, estimating that humanity moved from using about 70 percent of the biosphere's capacity in 1961 to roughly 120 percent by the late 1990s. The carbon component, the area of forest needed to sequester fossil-fuel emissions, is typically the largest and fastest-growing share. Footprint analysis is thus a sustainability accounting tool that renders an abstract idea, living within ecological limits, into a single comparable balance sheet.