Example: Utility Functions for Car Evaluation

Consider the root attribute of the Car Evaluation Model. According to the tree of attributes, the root attribute CAR depends on two lower-level attributes: PRICE and TECH.CHAR. Thus, the utility function that corresponds to CAR maps all the combinations of values of PRICE and TECH.CHAR. into the values of CAR (see the scales of these attributes). The function is defined by the table shown below.

Interpretation

The attributes PRICE and TECH.CHAR. have three and four values, respectively, so the number of rows in the table is 3×4=12. Each row provides a value of CAR for one combination of the values of PRICE and TECH.CHAR. Interpreted as an elementary decision rule, the fourth row, for example, means the following:

if PRICE=medium and TECH.CHAR.=bad then CAR=unacc.

See also

Representing this and other utility functions using complex rules.

All utility functions defined in the Car Evaluation Model.

Options evaluated in the Car Evaluation Model.