With the awareness of their environmental performance, countries can provide strategies and policies to improve their environmental performance. Thus, countries can contribute to their own economic development by increasing their environmental performance. Therefore, measuring the environmental performance of countries is of great importance. Environmental performance of countries can be measured by the Environmental Performance Index (EPI). EPI consists of two factors, environmental health and ecosystem vitality. Its factors are environmental protection components, and environmental protection components are environmental protection variables. In this context, the research has two purposes. The first of these,To measure the latest and up-to-date environmental performances of the G7 group countries for 2018, using CODAS and TOPSIS multi-criteria decision-making methods (MCDM) over the values of EPI components. The second is to determine which MCDM method can be used to explain the EPI values of countries the most. According to the findings, the ranking of countries' environmental performance with the CODAS method was determined as England, France, Japan, Germany, Canada, Italy and the USA. According to the TOPSIS method, this ranking was determined as England, France, Germany, Japan, Canada, Italy and the USA. According to another finding, it has been observed that there is a significant, positive and very high relationship between the EPI values of the countries and the values measured by the CODAS and TOPSIS methods. According to this result, it was evaluated that EPI can be explained by both methods. In addition, it has been concluded that the correlation value between TOPSIS values of EPI within the scope of the research is higher than the CODAS method, so it can be explained better with the TOPSIS method compared to the EPI CODAS method. In the literature, in order not to find a study measuring the environmental performance of countries with CODAS and TOPSIS methods, it was evaluated that the study in question contributed to the literature, since the findings obtained as a result of the research became a data set for future studies.

Keywords: Environmental Performance, Environmental Performance Index, CODAS, TOPSIS