Logical Decisions - Classweb

3. Click on the “Structure” tab in the Preference Set dialog
box.
4. Click on the "Performance" line in the box called "Goals
with a MUF." Both the "Best Truck" and "Performance"
lines should be highlighted, showing that both goals
will have their own MUF.
We will use the defaults for the other options in the dialog box, so
click OK to close it.
Defining Preferences for Individual Measures
Next you will tell LDW how to convert different levels on each
measure into common units (called utility). The formula to do the
conversion is the measure's Single-measure Utility Function (SUF -
- see page 3-4 for a brief discussion of SUFs).
LDW assigns the least preferred level on each measure a utility of
zero (0.0) and the most preferred level a utility of one (1.0). The
SUF defines how to convert intermediate levels to utility. As a
default, LDW uses a straight line (linear) conversion. Intermediate
levels are assigned utilities that are proportional to their distance
from the endpoints, so that a graph of levels vs. utility is a straight
line.
Assume that a straight line adequately models your preferences
concerning Price and Fuel Economy. You could check this by
using the mid-level splitting technique described on page 9-16.
Entering a Non-Linear SUF. Let's also assume that for Power you
don't feel that a straight line SUF is right. Suppose you feel that
130 horsepower is about the right amount and that anything under
about 115 horsepower is starting to get underpowered.
Using the mid-level splitting method, you find that you prefer a
change from 109 to 130 hp and a change from 130 to 175 hp
equally. Although the change from 175 to 130 is larger than from
130 and 109, horsepowers near 109 are starting to seem
uncomfortably low, making each hp change more important in
this range. This means that 130 hp is your mid-preference level for the
range from 109 to 175 hp.
To describe this to LDW, you use the Assess::Common Units
option.:
Section 4 -- Introductory Tutorial 4-11