Information Technology Reference
In-Depth Information
ii. Repair
iii. Failure mode analysis
b. External failure costs—the cost of detecting errors after shipping the product.
Examples of external failure costs are:
i. Complaint resolution
ii. Product return and replacement
iii. Help-line support
iv. Warranty work
The costs of finding and repairing a defect in the prevention stage is much less
that in the failure stage (Boehm, 1981; Kaplan et al. 1995).
Internal failure costs are failure costs that originate before the company supplies
its product to the customer. Along with costs of finding and fixing bugs are many
internal failure costs borne outside of software product development. If a bug blocks
someone in the company from doing one's job, the costs of the wasted time, the
missed milestones, and the overtime to get back onto schedule are all internal failure
costs. For example, if the company sells thousands of copies of the same program,
it will probably require printing several thousand copies of a multicolor box that
contains and describes the program. It (the company) will often be able to get a
much
better deal by booking press time with the printer in advance. However, if the artwork
does not get to the printer on time, it might have to pay for some or all of that wasted
press time anyway, and then it also may have to pay additional printing fees and rush
charges to get the printing done on the new schedule. This can be an added expense
of many thousands of dollars. Some programming groups treat user interface errors
as low priority, leaving them until the end to fix. This can be a mistake. Marketing
staff needs pictures of the product's screen long before the program is finished to get
the artwork for the box into the printer on time. User interface bugs—the ones that
will be fixed later—can make it hard for these staff members to take (or mock up)
accurate screen shots. Delays caused by these minor design flaws, or by bugs that
block a packaging staff member from creating or printing special reports, can cause
the company to miss its printer deadline. Including costs like lost opportunity and
cost of delays in numerical estimates of the total cost of quality can be controversial.
Campanella (1990) did not include these in a detailed listing of examples. Juran
and Gryna (1988) recommended against including costs like these in the published
totals because fallout from the controversy over them can kill the entire quality cost
accounting effort. These are found very useful, even if it might not make sense to
include them in a balance sheet.
External failure costs are the failure costs that develop after the company supplies
the product to the customer, such as customer service costs, or the cost of patching a
released product and distributing the patch. External failure costs are huge. It is much
cheaper to fix problems before shipping the defective product to customers. The cost
rules of thumb are depicted in Figure 1.2. Some of these costs must be treated with
care. For example, the cost of public relations (PR) efforts to soften the publicity
effects of bugs is probably not a huge percentage of the company's PR budget. And
thus the entire PR budget cannot be charged as a quality-related cost. But any money
Search WWH ::
Custom Search