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MCE: Eigen Values Calculations from Pair Wise Comparisons. Addition to Exercise 2-8. Pair Wise Comparison.
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MCE: Eigen Values Calculations from Pair Wise Comparisons. Addition to Exercise 2-8
Pair Wise Comparison. • The analytic hierarchy process (AHP) is a multi-criteria decision making method that employs a procedure of multiple comparisons to rank order alternative solutions to a multi-objective decision problem.
The Calculation of eigenvector from the pairwise comparison values requires a lot of work in terms of matrix algebra. • The method presented here is an approximation that suits to a good degree of accuracy in terms of eigenvalues.
Step-2 • Complete the upper diagonal values of the pair wise matrix. • If ‘A’ is 5 time of ‘B’ means ‘B’ is 1/5 times of ‘A’. • In the next diagram shaded values shows these values.
Step-4 • Calculate the sum of each column.
Step-5 • Divide the values in each cell by its column’s sum. • Eg: Col-1: 1/16, 3/16 ….. Col-2: 0.333/15.33, 1/15.333 etc …
Step-6 • Sum the weights in each row. (R1, R2, R3 …) • Add the results … Sum = (R1 + R2 + R3 + R4 + R5 + R6).
Step-7 • Get the ratio of each of the individual row’s sum to the resulting sum. • Eg. 0.379/6 = 0.063 etc .. • The Weights we get are the approximated weights as in the values obtained through Idrisi.
References: • The method for conversion taken from the lecture notes: • mat.gsia.cmu.edu/classes/mstc/multiple/node4.html • For the exact values calculation refer to the attached paper • The Analysis of the Principal Eigenvector of Pairwise Comparison Matrices; András Farkas • Excel file with the auto-calculation is also attached. • A very good software for auto conversion from pairwise values is; • http://www.isc.senshu-u.ac.jp/~thc0456/EAHP/EAHP_manu.html