Logical Decisions - Classweb

A probability of less than 0.5 for the more preferred possibility of
alternative A corresponds to the third case in the table above,
where big K is greater than 0 and the small k i sum to less than 1.
Here, a low utility on any one measure leads to a low overall
utility (destructive interaction).
Defining Interactions in LDW. LDW lets you define interactions
in several ways --
! By using an additive MUF formula (no interactions).
! By assessing a second tradeoff.
! By assessing a probabilistic tradeoff.
! By directly entering the small k for one measure.
! By directly entering the small k for all measures.
Generally, you define interactions after the weights have been
assessed. If you define the MUF formula to have no interactions,
you don't need to enter any additional information. This is the
default.
To assess a second tradeoff between two measures, LDW displays
a list of the existing tradeoffs and asks you to select one. Then
LDW asks you to directly define the second tradeoff using the
"free float" tradeoff assessment option.
If you have used a weight assessment method other than
tradeoffs, LDW will let you select any two active members and
define a tradeoff between them.
To assess a probabilistic tradeoff, LDW again asks you to select an
existing tradeoff. LDW then constructs a probabilistic tradeoff
question for the members in the original tradeoff and asks you to
enter the probability that makes the two alternatives equally
preferred. Again for other assessment methods you can select
any two active members to use in the question.
Directly entering the small k for one active member lets LDW
compute the complete MUF formula. Usually you will compute
the small ks using an additive MUF formula first and then select
an adjustment. If you enter a small k smaller than the one
computed for the additive formula, you will have a big K greater
than zero, indicating destructive interaction.
Section 9 -- In Depth 9-63