# Towards a Single Integrative Metric on the Dynamics of Social-Environmental Systems
## 3 Empirical Evidence for IMoSES Applications
Other energy or natural resources could replace ET as the ecological foundation for an SES. Historical data based on 18 PEs across the ADB (1992-2016) and on subnational scales in four countries for 2016 show that the IMoSES captures different aspects of SES function and dynamics. Although the IMoSES values and changes over time will be different when more countries are included, the unit of USD\({}^{2}\) yr\({}^{-2}\) pers\({}^{-2}\) mm\({}^{-1}\), or USD yr\({}^{-1}\) pers\({}^{-1}\) mm\({}^{-1}\), will remain the same and permit direct comparisons between PEs. An effort to calculate IMoSES for all countries globally will tell us about their magnitudes, differences, changes over time, and potentials. However, attention is needed to identify the appropriate values of \(\kappa\) and apply them consistently for comparisons among countries and over time. PDSI, HDI and SDI are used as the two independent metrics to demonstrate the effectiveness of IMoSES. The strong correlations with PDSI indicate that IMoSES changes with environmental conditions, similar to the idea behind the environmental Kuznets curve. These results present several avenues for future research. First, it is necessary to investigate why other environmental indicators in place of PDSI, HDI and SDI (e.g., temperature, precipitation, CO\({}_{2}\) emission, N\({}_{2}\)O emission, land use, etc.) exhibit different relationships with IMoSES, in order to explore how well IMoSES aligns with various indicators of environmental vitality [60]. Second, research on the relationship between IMoSES and other social indicators (e.g., life expectancy, educational attainment, gender equality) would increase understanding of the alignment between GDP and aspects of social well-being that together encapsulate the idea of economic development. Three, the metric we developed may be useful for the assessment of progress towards the Sustainable Development Goals (SDGs; [[https://sdgs.un.org/goals](https://sdgs.un.org/goals)]([https://sdgs.un.org/goals](https://sdgs.un.org/goals)), accessed on 1 June 2020) by tracking the temporal trajectories of IMoSES across countries during the recent past to reveal how this concept maps onto SDG progress for specific countries. Specifically, our metric can be related to a number of goals, including ending poverty and promoting decent work and economic growth, human wellbeing, and climate action. Relatedly, more efforts are needed to explore if integrated metrics, including IMoSES, can be used in policy development and decision making. Here, lagging components of the metric can be selected for additional analysis and policy development. For example, stagnant or declining GDP relative to the other two-pillar components may suggest a need for policy action to raise domestic income. Stagnant or declining NPP relative to the other two indicators may indicate a need for policies to improve the environmental conditions of PEs. Future research could also extend the calculation and analysis of IMoSES to other countries, regions, biomes, or development stages (e.g., higher-income countries vs. lower-to-middle income countries) [61]. A potential revision of the proposed IMoSES is to standardize its values through normalization for a given scale (e.g., by region, continent, or time period). These steps would enable us to group countries by IMoSES in a way that is akin to \"convergence clubs\" in economics--by identifying countries that exhibit similar growth trajectories [62]. We provided preliminary evidence that \"IMoSES clubs\" are likely, as distinct over- and under-performers were evident within the three regional categories of ADB PEs (East Asia, Central Asia, and the Middle East). Among the Middle Eastern countries, Turkey had higher IMoSES than other countries in its group. In Central Asia, Kazakhstan had the highest IMoSES. From a global perspective, it would be important to identify countries with similar IMoSES trajectories, which are indicative of similar dynamics among the three pillars of sustainability.