Developing interpretive structural modeling based on factor analysis for the water-energy-food nexus conundrum.

Factor identification and analysis are effective ways to explain and quantify complex relationships in the water-energy-food nexus (WEF-nexus). It has been acknowledged that factors in the WEF-nexus vary by time, level and location, but the hierarchy between factors has been largely ignored. Taking advantage of the interpretive structural modeling (ISM) method, this paper presents an identification and analysis on the interwoven factors in an urban WEF-nexus in Beijing. As a result, 87 representative factors have been identified and classified, with a hierarchy structure established by ISM. Based on the relative importance of given factors, factor hierarchy structure shows that the energy system in the core nexus is the essential system and is critical to promoting the WEF-nexus in Beijing; factors from peripheral nexuses - such as population and vehicle volume - also have a significant influence on nexus governance. Furthermore, integrated policies from subsystems within the core nexus or between the core and peripheral nexuses are critical to secure WEF in Beijing. Factor analysis suggests that the portrayed nexus structure could provide valuable references for further quantification and decision making.