Logical Decisions - Classweb

Similarly, a single member can have a large effect in reducing the
overall utility if there is destructive interaction, but can only have
a small effect in increasing the overall utility.
Defining Interactions Between Measures. Determining a
multiplicative MUF formula requires one more piece of
preference information than an additive MUF formula. The
additional information lets LDW compute the multiplicative MUF
formula's interaction scaling constant, big K.
The additional piece of information can be:
! a second tradeoff between two members that were
already involved in a tradeoff,
! a response to a probabilistic question that gives
additional information about two members already
involved in a tradeoff, or
! defining the exact value of one scaling (weighting)
constant.
You usually define a second tradeoff between two active
members by comparing an alternative where they are at extreme
levels to one where they are at intermediate levels. It helps if the
two members are nearly equally weighted.
For example, suppose that we have done a tradeoff between
power and fuel economy and found that the decision maker feels
that they are equally important. Now we define a second tradeoff
between the two measures with a dialogue that might go as
follows:
Q: We already talked about the tradeoff between
power and fuel economy. Now I want to look at
those measures again to define their interaction.
Suppose a truck has 175 hp (the most preferred
level) but only gets 16 mpg (the least preferred
level). Call this alternative A. Now suppose a
second truck is the same as the first but has 130 hp
(already defined as the mid-preference level) and
gets 20 mpg (also the mid-preference level). Call
this alternative B. Which of these two alternatives
would you prefer?
Section 9 -- In Depth 9-59