Sugar and sugar lump are from the fundamental goods in Iran that with respect to their share in producing the agricultural products and also their role as an end consumed good or their supplementary and mediatory role in producing much of the family consumed goods, hare received attention. So, this protect has encountered the governmental heavy interferences, price severe fluctuations, vast production in the countries all over the world, also it hey a very vast market in Iran and all around the world, so this industry, requires an intensive survey either with respect to the production and its expense or from the consuming point of view. The purpose of this survey is to study about the effect of the concentration index on the technical efficiency of the sugar and (sugar lump) producing factories through estimating Boundary the required information collected from sugar production factories for years 1384-88, and after estimating the Tran slog production function with combinational data, the effective factors on their technical efficiency such as the amount of concentration, have been evaluated, too. The effective factors on the technical efficiency gas and residue (mazut) to beet, antiquity, extraction coefficient, silo drop, the number of work forces with the education higher than the licentiate's degree and the observation year. The results obtained from this model show that the average of the evaluated technical efficiency in industry is %89 and also average increases with increasing the inefficiency concentration in the industry.

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