Information Technology Reference
In-Depth Information
10.5.1 Utility
Utility is the extent to which a user's needs are met and a correct product is used
under conditions permitted by its specifications. In other words, a product that is
functioning correctly is now subjected to inputs that are valid in terms of the
specifications. Irrespective of the issues such as performance, ease and cost
effectiveness have to be tested. If the product is not cost effective then there is no
point in buying it. Therefore, when considering the buying of an existing product,
the utility of the product should be tested first, and if the product fails, testing
should be stopped.
10.5.2 Reliability
Another aspect that must be tested is reliability. Reliability is a measure of the
frequency and criticality of product failure. Reliability has to do with the quality of
measurement. Failure is a consequence of fault. In other words, it is necessary to
know how often the product fails and how bad the effects of that failure can be.
When a product fails, an important issue is how long it takes to repair the results of
the failure. This point is frequently overlooked in instances such as if the software
fails and completely erases the information needed. The information can be
retrieved using backups, but the system will be inoperable for a few days, resulting
in the low reliability of the system. There are four general classes of reliability
estimates, each of which estimates reliability in a different way. They are:
• Inter-Rater or Inter-Observer Reliability Used to assess the degree to which
different raters/observers give consistent estimates of the same phenomenon.
• Test-Retest Reliability Used to assess the consistency of a measure from one
time to another.
• Parallel-Forms Reliability Used to assess the consistency of the results of two
tests constructed in the same way from the same content domain.
• Internal Consistency Reliability Used to assess the consistency of results
across items within a test.
10.5.3 Robustness
Another aspect of every product that requires testing is its robustness. Robustness
essentially is a function of a number of factors, such as the range of operating
conditions, the possibility of unacceptable results with valid input, and the
acceptability of effects when the product is given invalid input. A product with a
wide range of permissible operating conditions is more robust than a more
restrictive product. A robust product should not crash when the product is not used
