Sammenlign metoder

	STIRPAT Model	Water Footprint Analysis
Fagområde	Environmental Sociology	Environmental Sociology
Familie	Regression model	Process / pipeline
Oprindelsesår	1997	2011
Ophavsperson	Thomas Dietz & Eugene A. Rosa; Richard York	Arjen Y. Hoekstra (with Chapagain, Aldaya & Mekonnen)
Type	Log-linear stochastic regression model of environmental impact drivers	Volumetric freshwater-appropriation accounting pipeline
Oprindelig kilde	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.	Hoekstra, A. Y., Chapagain, A. K., Aldaya, M. M., & Mekonnen, M. M. (2011). The Water Footprint Assessment Manual: Setting the Global Standard. Earthscan. ISBN: 9781849712798
Aliasser	Stochastic IPAT, STIRPAT Regression, Stochastic Impacts by Regression on Population Affluence and Technology, Dietz-Rosa Impact Model	Water Footprint Assessment, Blue-Green-Grey Water Accounting, Virtual Water Analysis, Hoekstra Water Footprint
Relaterede	4	3
Resumé	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.	Water footprint analysis is a volumetric accounting method that measures the appropriation of freshwater used to produce the goods and services consumed by an individual, community, business, or nation. Formalized in Arjen Hoekstra's Water Footprint Assessment Manual of 2011, it decomposes water use into three components: the green water footprint (rainwater consumed, mainly through crop evapotranspiration), the blue water footprint (surface and groundwater consumed), and the grey water footprint (the volume of freshwater needed to dilute pollution to meet ambient quality standards). By tracing water through supply chains and aggregating these components, the method reveals how much and what kind of water lies behind products and consumption — including virtual water embedded in trade — and then assesses whether that appropriation is sustainable relative to local water availability and pollution-assimilation capacity.