Logical Decisions - Classweb

of the hierarchy be made up of evaluation measures only. This
means that at least one goal must be made up of only measures.
Since goals may be "measurable" at different levels of the
hierarchy, LDW lets you have both measures and goals as
members of a higher level goal. In the truck example, the "choose
the best truck" goal might have three members, a measure called
Price, a goal called Quality and another goal called Features.
Each goal in LDW has a name, which can be up to 255 characters,
an optional ID number, optional comments, and a nominal utility
that LDW may use in the preference assessment process described
on page 9-31. Each goal also has a set of members, which can be
either measures or other goals. The View::Goals Hierarchy option
is described on page 6-5.
Defining Measures
Evaluation measures are the variables used to describe the
alternatives. They quantify the lowest level goals in the goals
hierarchy described on page 9-6. The measures completely
describe the alternatives for ranking purposes.
Measures must be quantitative or textual and specific enough to
let you assign a number, text description or probability
distribution for each alternative. Other than that, LDW puts few
restrictions on the form a measure may take. Measures can be
natural, such as the cost of a car, or constructed, such as a
five-point scale that describes a car's luxuriousness. Each
measure consists of units and a range from least preferred to most
preferred. The units may be continuous, such as horsepower, or
discrete, and there is no requirement that the ranges or units for
the different measures be comparable.
Measures whose desirability increases as the level increases (such
as miles per gallon, where 30 MPG is preferred to 20 MPG) are
called increasing. Measures where desirability decreases as the
level increases (such as Cost, where $30,000 is less preferred than
$20,000) are called decreasing. The most preferred level of a
measure is the highest level for increasing measures and the
lowest level for decreasing measures.
An ideal alternative is one with the most preferred level on all of
the evaluation measures.
9-8 Section 9 -- In Depth