Proportionality, Optimal Economic, the optimal correspondence between the structure of social production and the objectives involved in building communism at a given stage in the development of socialist society. It provides the best solution to the problems of socio-economic development, raises the efficiency of social production to the highest possible extent and contributes to satisfaction of the people’s requirements with the least expenditures of living and materialised labour. One criterion of optimal economic proportions in developed socialist society is their correspondence to the supreme goal of social production. The criterion of optimal production in industries, associations and enterprises is usually the maximum volume of quality products with the minimum expenditure. The time factor is also considered when proportions are being optimised: the best are correlations which help fulfil the tasks set with minimum outlays and in the shortest time possible. Proportions are optimised through a corresponding distribution of human, material and financial resources on the basis of numerous computer calculations, the comparison of all possible variants, and the selection of one regarded as best. The optimal variant maximally harmonises with the established criterion, i. e., it helps attain the highest possible end results in the plan period with the planned material and manpower resources, or planned final results (e. g., a certain volume of production) with the minimum expenditure of labour and resources. An important condition optimising economic proportions is the material and financial reserves necessary for a proportionate and balanced development. In accordance with the Resolution of the CC CPSU and the USSR Council of Ministers of July 12, 1979, "On Improving 295 Planning and Enhancing the Economic Mechanism’s Impact on Raising Production Efficiency and Quality of Work”, the Soviet state five-year economic and social development plan will provide, according to established standards, for material and financial reserves for the requirements of production, capital construction and RAD and, whenever necessary, reserve capacities as well. Reserves, whose size and content are optimal, are necessary to make effective structural changes in the economy, and to prevent partial imbalances which may arise from discrepancies of rates in the development of certain branches, from discrepancies between the structure of requirements and structure of production, etc. Proportions must be optimal not only in material production, but also in the sectors of the non-production sphere, as well as in the consumption structure (e. g., correlation between the consumption of different products, correlation between outlays for different purposes, such as food, clothing, cultural pursuits, rest and leisure, recreational travel, etc.) Under capitalism, economic proportions cannot be optimised. Intra-company and intra-production proportions are also periodically overturned because of the disproportional development of social production as a whole. In developed socialist society broad opportunities are provided to seize upon the advantages of the socialist economic system, to raise production efficiency and to optimise national economic proportions (see Law of Planned Balanced Development of the Economy; Economic Planning).