Logical Decisions - Classweb

This dialogue let us establish a tradeoff between cost and power
by identifying two alternatives that differ only in those measures
and that the decision maker prefers equally. The two equally
preferred alternatives are:
Alternative A: cost = $7000, power = 80 hp, and
Alternative B: cost = $9000, power = 160 hp.
LDW can now compute the relative weight for the two measures
(if the SUFs for the two measures have been assessed). LDW does
this automatically. You and the decision maker don't have to do
any computations. All you have to do is tell LDW when you
prefer two simple alternatives equally.
Assessing Tradeoffs with LDW. LDW simplifies the tradeoff
assessment process by keeping track of which measures you have
assessed. Initially LDW lets you select any two active members to
trade against one another. Once you have done one or more
tradeoffs, the program gives you a reduced range of choices. In
this way LDW ensures that you don't assess any unneeded
tradeoffs.
To compute a complete set of weights for a MUF, you must have at least
one tradeoff that includes each active member. If there are n members
you must assess n-1 tradeoffs.
Interpreting Directly Entered Weights
You can interpret directly entered weights as defining a pair of
equally preferred alternatives. In this interpretation, think of an
alternative that has the least preferred level on each of the active
members except one -- the member whose scaling constant you
are assessing, which has the most preferred level. This is the first
simplified alternative in the pair. Call it the "one member for
sure" alternative.
Next think of an alternative with well-defined uncertainties. This
alternative has a probability P of having all of the active members
at their most preferred levels (including the one you are
assessing) and a probability of 1 - P of having all of the active
members at their least preferred levels. This is the second
simplified alternative (well, maybe its not so simple). Call it the
"all or nothing" alternative.
9-48 Section 9 -- In Depth