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88 PART TWO MANAGING SOFTWARE PROJECTS

individual are often combined to develop project metrics that are public to a software
team. Project metrics are then consolidated to create process metrics that are public
to the software organization as a whole. But how does an organization combine met-
rics that come from different individuals or projects?
To illustrate, we consider a simple example. Individuals on two different project
teams record and categorize all errors that they find during the software process. Indi-
Because many factors vidual measures are then combined to develop team measures. Team A found 342
influence software errors during the software process prior to release. Team B found 184 errors. All other
work, don’t use
metrics to compare things being equal, which team is more effective in uncovering errors throughout the
individuals or teams. process? Because we do not know the size or complexity of the projects, we cannot
answer this question. However, if the measures are normalized, it is possible to cre-
ate software metrics that enable comparison to broader organizational averages.

4.3.1 Size-Oriented Metrics
Size-oriented software metrics are derived by normalizing quality and/or productiv-
ity measures by considering the size of the software that has been produced. If a soft-
ware organization maintains simple records, a table of size-oriented measures, such
? What data as the one shown in Figure 4.4, can be created. The table lists each software devel-
should we
collect to derive opment project that has been completed over the past few years and corresponding
size-oriented measures for that project. Referring to the table entry (Figure 4.4) for project alpha:
metrics? 12,100 lines of code were developed with 24 person-months of effort at a cost of
$168,000. It should be noted that the effort and cost recorded in the table represent
all software engineering activities (analysis, design, code, and test), not just coding.
Further information for project alpha indicates that 365 pages of documentation were
developed, 134 errors were recorded before the software was released, and 29 defects

Project LOC Effort $(000) Pp. doc. Errors Defects People

alpha 12,100 24 168 365 134 29 3
beta 27,200 62 440 1224 321 86 5
gamma 20,200 43 314 1050 256 64 6

• • • • • •
• • • • • •
• • • • • •

FIGURE 4.4
Size-oriented
metrics