Logical Decisions - Classweb

nth root of the product of the ratios, where n is the number of
alternatives.
Instead of waiting till you have entered all the needed ratios,
LDW computes the active member's weights each time you enter
a new ratio. LDW uses all the ratios you have entered so far as
the basis for its estimates. LDW uses a simple iterative procedure
to estimate the ratios you haven't entered yet based on those you
have. Thus, there is always a complete set of weights available. If
you don't want to enter all the ratios required by the AHP
process, you can stop any time the computed weights seem
reasonable to you.
Note that, if you want to use the "complete" AHP method, you
should use the "Analytic Hierarchy Process" method when
converting the measures to common units.
Both pairwise weight assessment methods focus on the members'
names rather than their ranges. Of course, it is possible to take
the ranges into consideration when assigning weight ratios. For
example, you could think of each ratio as a "mini-swing weight,"
and think of the relative importance of changing each member
from its most preferred to least preferred level. The "complete"
AHP method compounds this problem by not even using explicit
measure levels. Here you will need to think about the best and
worst performances for the members for the alternatives in your
analysis.
You should be considering the ranges for the members when
assigning weight ratios using the methods described above. If the
ranges or definitions of the members change, their weight ratios
should change. LDW does not automatically adjust any weight
ratios if you change a member. Thus, when you make changes
you should review any weight ratios you have assessed to see if
you should make any changes.
Assessing Weights by Comparing Pairs of Alternatives
The tradeoff method in LDW takes an indirect approach to
establishing the weights of the measures. This approach uses the
idea that equally preferred alternatives should have equal utilities.
LDW exploits this idea by having the decision maker identify
pairs of equally preferred alternatives that differ on two of the
active members. LDW uses these differences to identify the
implied relative importance of the two measures.
Section 9 -- In Depth 9-41