The identification of the real level of economic development of the region is an important condition to design effective regional development policy. Economic development is characterized by a large number of indicators. This study provides an approach for assessing the level of economic development based on the use of a comprehensive index, which is a convolution of initial indicators. The model involves the use of both a group of absolute indicators and a group of relative measures of dynamics. Each of the groups of indicators has its special data normalization procedure and its special method of convolution into a partial comprehensive index. The outcome of the evaluation is obtained by weighted multiplicative convolution of partial comprehensive indexes. In this study, the level of economic development of regions of Ukraine according to the data of 2017 has evaluated. As a result, Ukraine's regions were allocated into three groups: with the level of economic development above average, with the average level of economic development and with the level of development below average. The article suggests a way to determine the boundary values of the comprehensive index for grouping. Comparison of the obtained results of grouping with the results of clustering of the Ukraine's regions by the k-means method with the same data showed their identity. The article shows that Ukraine's regions can be allocated by the level of economic development into other number of groups.