This paper consists of the literature and practice investigation regarding measurements metrics of public sector performance. The proposed investigation begins with consideration of the features of the public sector and the difficulties to measure the performance due to multiple principals and multiple tasks. The analysis provides the limitations of performance measurement systems. Although a variety of performance measures exist, our investigation emphasizes need for creation of composite indicators (aggregate indicators) in the public sector used widely in infrastructure, health, social services, education, administration and other service areas. Despite the apparent simplicity of composite measures, our paper reveals that their use and interpretation raises several challenges: i) different methods and methodologies of constructing composite indicators (Data Envelopment Analysis (DEA), Free Disposal Hull (FDH) methodology, Principal Component analysis (PCA)); ii) the uncertainty influence on composite indicators; iii) the variation in performance due to factors beyond the control of managers or iv) the iterative consultative approach performance.