Integrated assessment modelling (IAM) or integrated modelling (IM) is a type of scientific modelling often used by the environmental sciences and environmental policy analysis. The modelling is integrated because environmental problems do not respect the borders between academic disciplines. Integrated assessment models therefore integrate knowledge from two or more domains into a single framework. Integrated modelling is referred to as assessment because the activity aims to generate useful information for policy making, rather than to advance knowledge for knowledge's sake. Integrated assessment modelling is that part of integrated assessment that relies on the use of numerical models.
Integrated assessment modelling has a long history, and scholars disagree on the first precedent. However, it became recognizable as a sub- or inter-discipline in the late 1980s with a focus on understanding and regulating acidification. Integrated assessment modelling was further developed in the area of climate change, inter alia in the context of the Energy Modeling Forum.
Notable centres of integrated assessment modelling are IIASA, MIT, Netherlands Environmental Assessment Agency, and International Futures. Notable scholars are Barry B. Hughes, Bill Nordhaus, Robert Mendelsohn, Rich Richels, Michael Schlesinger, Stephen Schneider, Richard Tol, John Weyant, and Gary Yohe.