“…As fundamental instruments of the research into SESs, correlation-regression and multicriteria assessment methods do not compete, but rather complement each other, thus forming a comprehensive system of complex research. The choice of factors influencing SESs development depends on aim and objectives of research, scale of the SESs, so, they can include performance indicators or its prerequisites (Bilan et al, 2020;Bobenič Hintošová et al, 2018;Kostiukevych et al, 2020) In the first stage of such a research, the condition of a PPC, for instance, corporate staff, marketing system quality, economic performance, socioeconomic development of a country/region, etc., is assessed by means of applying multi-criteria assessment methods (Gedvilaitė, 2019;McLaren et al, 1998;Molly, 2018;Oželienė, 2019;Strezov et al, 2017;Volkov, 2018). In the second stage, correlation-regression analysis is invoked to find out what impact this condition had on different SES parameters, e.g., what impact the quality of corporate staff had on corporate economic performance.…”