Logical Decisions - Classweb

Figure 9-12. Quantitative range vs. weight example.
The difference in cost between A and B is just matched by the
improvement in performance from A to B. Based on this tradeoff,
equal weights are assessed for the Cost and Performance
measures. The resulting MUF results in equal utilities for A and B
as they should have.
Now suppose the range for Cost is increased from $100 to $300
instead of $100 to $200. If there is no change in weights, the
computed utility for B changes, because it is no longer at the least
preferred level for Cost. The utilities for A and B are no longer
equal, even though we still find them equally desirable.
The way to bring things back into sync is to change the relative
weights for Cost and Performance. In particular, since the range
for Cost has doubled it should get twice as much weight as before.
This means that Cost will have twice the weight of Performance.
When we make the weights sum to 1.0, this means that Cost will
have a weight of 0.67 and Performance will have a weight of 0.33.
When we compute the utilities of A and B, we find that with the
new weights they are once again have equal utilities.
Section 9 -- In Depth 9-53