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58 Decisions involving multiple objectives: SMART
The decision problem presented in this chapter was designed to be
amenable to hand calculations. This would, however, be an extremely
tedious way of approaching larger problems, and for these it would
be necessary to use a computer. Packages available include HIVIEW
and V·I·S·A. These have all the features which are needed to carry
out SMART-type analysis, including a facility which allows the user to
construct and modify value trees on-screen.
We stated in the Introduction that this method is normally applied
where risk and uncertainty are not major concerns of the decision maker.
However, it is possible to apply the method even in these circumstances
by treating risk as an attribute. Wooler and Barclay 6 describe such an
application involving a strike-prone production facility. (The analysis
involved a group of managers in a decision conference.) A value tree
was used to decompose ‘risk’ into lower-level attributes such as ‘risk of
strikes’ and ‘public relations risks’, and the various strategies were scored
in terms of their performance on these attributes using direct rating (for
example, the least risky option was allocated the highest value). A
second part of the value tree dealt with the benefits of the strategies and
these were similarly scored. A graph such as Figure 3.7 was then used to
display the aggregate risk of strategies against their aggregate benefits
(rather than costs against benefits). We will consider a similar approach to
risk in the context of a group decision problem in Chapter 13. However,
a number of techniques have been specially designed to handle decisions
involving a large element of risk and uncertainty, and we will consider
these methods in the following chapters.
Exercises
(1) Formulate a value tree to identify the attributes which are of concern
to you when choosing a vacation.
(2) You need a word-processing package for the personal computer in
your office. Because your employer will pay for the package you
are not concerned about the cost, but you would like a package
which is as easy to use as possible and which also has a wide range
of functions such as a thesaurus, spell checker and graphics. After
discussing the matter with a friend who is something of an expert in
this field, you identify seven potential packages and allocate values
to them to reflect their ease of use and available facilities. These
values are shown below (0 = worst, 100 = best).