Logical Decisions - Classweb

Each cell in the matrix represents the ratio of the row alternative's
performance on the measure to the column alternative's
performance.
You complete the AHP assessment process by entering
performance ratios into the proper cells. You will be done when
each cell has the correct performance ratio.
Your task is not quite as bad as it seems. Since the cells on the
diagonal of the matrix compare the performance of each
alternative to itself, the performance ratios in those cells must all
be one.
You don't have to enter these obvious ratios. LDW uses the
diagonal cells to show the computed utilities for the alternatives
instead of the forced 1.0 ratios.
In addition, the ratio of a row to a column alternative must be the
inverse of the ratio of the column alternative to the row
alternative. For example, suppose alternative A is in row and
column 1 of the matrix and alternative B is in row and column 2.
If A's performance on the measure is twice as good as B's then the
cell for row 1 and column 2 should have the ratio 2.0. Similarly,
the cell for row 2 and column 1 should have the ratio 0.5, since it
is the ratio of B's performance to A's.
These ratios are inextricably linked, so when you enter the ratio
for one cell, LDW automatically enters its inverse in the
corresponding cell on the other side of the matrix.
This means you only have to enter as many ratios as there are
cells above the diagonal row in the matrix to complete your
assessment.
Each time you enter a ratio, LDW marks the cell in blue and
updates the level in the corresponding cell on the other side of the
diagonal. LDW also marks this cell in blue. You will have
completed your assessment when all the cells in the matrix are
marked in blue.
The developers of the AHP method have provided some cues to
help you set the performance ratios. They have defined the
following five terms along with a corresponding performance
ratio:
Ratio Term Explanation
9-28 Section 9 -- In Depth