can review before making material choices. The Environmental Resource Guide, which was published by the American Institute of Architects (AIA) between 1992 and 1999, combined quantitative with qualitative analysis of key product areas, along with case studies of specific buildings (Demkin, 1998). LCA is also being applied to building assemblies and whole buildings (through design tools that I will cover later in this chapter). The widespread use of LCA by designers, however, probably depends on the functional integration of LCA information into computer-aided design (CAD) and drafting tools (Levin, 2000). Despite rapid progress in recent years, there is much work that needs to be done with both LCA systems, and with intermediary tools using the life-cycle approach. While it is probably true that one single standard kind of LCA would not be appropriate, many of the existing differences in LCI data sets and LCIA impact categories are needlessly incomparable, making for confusion and impracticality. In such a young field, this is understandable and there is a substantial amount of consultation to overcome these problems. Europe is several steps ahead of North America in this regard. But the US Dept. of Housing & Urban Development (HUD) in April, 2001 convened a workshop/think tank of the top experts on LCA in building to consider the state of the art, and chart directions for the field that could practically impact on the housing industry in the U.S. (National Association of Home Builders (NAHB) Research Center, 2001a). It is planning similar sessions to be held periodically. Coupled with projects like the NREL US LCI Database project mentioned above, LCA activity should continue to grow in both quality and practicality.