Information Technology Reference
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stated). Results of simulations can only be as good or valid as
the assumptions that underlie them.
Hardware : Although hardware tends to be more reliable than
software, unanticipated hardware malfunctions can occur,
with possibly serious consequences.
Altogether, we need to be particularly cautious in relying on com
puters for answers to questions. Every largescale software package
has errors. Some may be known, but we should expect to find new er
rors, even in programs that have undergone extensive testing. All of
this suggests that we should not fully rely on computers in our work.
As a practical matter, the best defense against possible errors
may be healthy skepticism and constant checking. If we do not auto
matically assume that a computer has produced the correct results,
then we will compare its results with those from other sources. We
also can ask ourselves if computerproduced results are reasonable.
In reviewing models and simulations, we can ask what variables are
used, how relationships were determined, and what assumptions
were made. Of course, modern computers have a reasonable track
record in producing helpful results—but they also malfunction (e.g.,
crash) from time to time.
With this record, it may be best to begin by assuming that com
puters are producing unreliable results until you have evidence that
the data in front of you are correct. When using word processors,
databases, and spreadsheets, such checking often is easy—you just
look at what is displayed on your screen and compare it with what
you intended. When using unfamiliar software or when working on
more complex problems, you may need to take more extensive ac
tion to check. And if you will be investing your life savings—where
the risks are high—you might want considerable evidence of testing
and accuracy before proceeding.
For problems that a computer can solve, what
process should I use to get an answer?
Sometimes a problem at hand is relatively easy; for example, we
may want to add the cost of three items to doublecheck a bill we
received from our telephone company. To do so, we likely can iden
tify a software package on our computer (perhaps a calculator or
 
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