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Total Factor Productivity (TFP) is a measure for assessing the productivity of a firm or organization. The level of productivity score of a firm shows that how the firm succeeds in optimizing the usage of sources and producing more outputs by certain level of inputs. Nowadays the productivity growth has a crucially important role in economics and firms competition. The industrial countries increase their outcomes not necessarily through more inputs but, by making growth in productivity. Some of the duties of executive organizations of Iran which is explained in the 4th program of development is to determine the productivity growth rate of the related products, organizing the programs, making some solutions for increasing the productivity such as that of GDP growth to be at least 31.3% and average growth of labor, capital and TFP to be at least 3.5%, 1%, 2.5% respectively. For achieving these targets, firstly, the productivity score should be calculated for every organization during previous periods of their activities. Then the effective factors of productivity growth should be determined and forecasted for the next period, to increase the productivity at least by 2.5%. In this paper we present a method based on productivity growth indexes and generalize inverse DEA. Using the proposed method, the productivity score of previous periods are calculated. Then the value of input and output changes for the next period is determined. This method is applied for a case study at National Iranian Oil Company

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Using productivity index for investigating a firms’ performance makes it possible to evaluate efficiency of the production system and cost at the same time. In this study the Total Factor Productivity (TFP) of several sugar cane varieties in Imam Khomeini Cultivation and Processing Center in Khuzestan Province is compared. Two hundred and forty eight farms are categorized on the basis of variety years old and then Tornqvist-Tiel Productivity Index is employed for calculating TFP for each sugar cane farm. The investigated sugar cane varieties include CP57-614, CP69-1062 and CP48-103. Results revealed that year long utilization system gained the lowest TFP among utilization systems in all the mentioned varieties. The most suitable utilization system according to the TFP index is biennial for CP57-614 variety, triennial for CP69-1062 and five years for the CP48-103 variety. Triennial CP57-614 variety has the most partial productivity in fertilizer. On the other hand, the six year long plant of the forgoing variety exhibits the largest partial productivity in water. The largest partial productivity in machinery is shown in biennial CP69-1062 variety. Among these varieties, triennial CP48-103 one has the largest partial productivity per unit area cultivation.