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The ranking coefficient method adopted by Kendall is quite simple and easy to apply. In this technique, the component areal units are ranked according to the per hectare yield of crops and the arithmetical average rank, called the ranking cotfficientfor each of the component areal units is obtained. It is obvious that a component areal unit with relatively high yields will have low ranking coefficient, indicating a high agricultural productivity. In other words, if a component areal unit (district in India) was at the top of every list of crops, it would have a ranking coefficient of one and thus having the highest agricultural productivity. Opposite to this if the areal unit was at the bottom of every list, it would have a ranking coefficient equal to total number of units considered, showing the lowest agricultural productivity among the constituent units.
The ranking coefficient method can be illustrated with the help of an example. Suppose, in a region, there are 80 component areal units (district/tehsil). In a district ‘x’, on the basis of average yields, wheat ranks 5th, rice 12th, gram 20th, cotton 21st, barley 24th, and sugarcane 38,h, pulses 40th and mustard 54th. The average rank, called the ranking coefficient of the district x’ would be;
5 4-12 4- 20 4- 21 4- 34 4- 38 4- 40 4- 54
Agricultural Productivity =
= 28
8 crops
The average ranked position of all the units of the region is, thus, calculated and arranged in an ascending order or descending array. The array is divided into three equal parts to ascertain the low, medium and high agricultural productivity. With the help of the index scale, the agricultural productivity of each unit can be ascertained and plotted. The Kendall’s technique was applied to determine the agricultural productivity of India at the district level. The agricultural data for each of the districts were computed for the years 2003 to 2006. The ranking coefficients thus obtained were plotted in Fig. 10.2.