assessment improvement of financial performance through representative of indexes by grey relational analysis (gra) (case study: urban water and sewage companies)

assessing financial performance is one of the most important in functional domains, because financial information is considered for the basis of making decisions. organizations use various indexes for assessing performance in quantitative techniques. although these sorts of assessments provide useful information, but the comprehensive concept will never be concluded because of considering all the indexes without regarding their importance. so identifying the representative of indexes, using scientific models will be so effective for the results. in this study according to the financial indexes of water and waste water companies (60 indexes) using grey relational analysis theory, the representative of indexes (25 indexes) are selected for assessing performance. then the performance of the water and waste water companies will be ranked in two conditions: without representative of index and with representative of index on the basis of topsis. the results will show weak correlation between the above said conditions (0.217). the grey relational analysis model can be used as an effective tool for selecting indexes to improve performance assessment.