The Cost of Bugs


As you will learn in Chapter 2, software doesn't just magically appearthere's usually a planned, methodical development process used to create it. From its inception, through the planning, programming, and testing, to its use by the public, there's the potential for bugs to be found. Figure 1.2 shows an example of how the cost of fixing these bugs can grow over time.

Figure 1.2. The cost to fix bugs can increase dramatically over time.


The costs are logarithmicthat is, they increase tenfold as time increases. A bug found and fixed during the early stages when the specification is being written might cost next to nothing, or $1 in our example. The same bug, if not found until the software is coded and tested, might cost $10 to $100. If a customer finds it, the cost could easily be thousands or even millions of dollars.

As an example of how this works, consider the Disney Lion King case discussed earlier. The root cause of the problem was that the software wouldn't work on a very popular PC platform. If, in the early specification stage, someone had researched what PCs were popular and specified that the software needed to be designed and tested to work on those configurations, the cost of that effort would have been minimal. If that didn't occur, a backup would have been for the software testers to collect samples of the popular PCs and verify the software on them. They would have found the bug, but it would have been more expensive to fix because the software would have to be debugged, fixed, and retested. The development team could have also sent out a preliminary version of the software to a small group of customers in what's called a beta test. Those customers, chosen to represent the larger market, would have likely discovered the problem. As it turned out, however, the bug was completely missed until many thousands of CD-ROMs were created and purchased. Disney ended up paying for telephone customer support, product returns, replacement CD-ROMs, as well as another debug, fix, and test cycle. It's very easy to burn up your entire product's profit if serious bugs make it to the customer.



    Software Testing
    Lessons Learned in Software Testing
    ISBN: 0471081124
    EAN: 2147483647
    Year: 2005
    Pages: 233

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