 Typically, researchers examine specific elements of formula_23 rather than attempting to aggregate.The big picture result is that by collecting data on average economic sector transactions formula_16 and average sector emissions formula_18, it is possible to make quick predictions about the full supply chain emissions associated with a product of interest by representing the product as marginal changes in production from relevant sectors formula_15.Researchers at the Green Design Institute of Carnegie Mellon University began developing a web-based tool for performing an EIO-LCA in the 1990s.