The work of the present study is focused on a variety of issues in the area of stabilization policies for large macroeconometric models under informationally decentralized structures. Despite the relatively simple structure of the decentralized economic models, there are interesting problems concerning the interplay between information, decision and control-regulation. Many of them, however, are still unresolved. We intend that the study, which contains a number of critical issues and potential approaches to large and decentralized systems, should be a contribution to the theory of decentralized macroeconomic policy and planning as an extension of the conventional approach founded by R. Frisch, J. Tinbergen and H. Theil. This broad and important assignment is extremely complicated and unexplored, so that we have the study limitations inherent in current economic and econometric practice. The study is developed in two parts consisting of theoretical and practical methods.