Information Technology Reference
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methods and tools, the use of standards, the effectiveness of management, and the
performance of development systems can be used in this category.
Productivity is another process metric and is calculated by dividing the total
delivered source lines by the programmer-days attributed to the project in line of
code (LOC)/programmer-day.
SOFTWARE RESOURCE METRICS
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5.7
These include:
Elapsed time
Computer resources
Effort expended
On tasks within a project, classified by life-cycle phase or software function
On extra-project activities training
As with most projects, time and effort are estimated in software development
projects. Most estimating methodologies are predicated on analogous software pro-
grams. Expert opinion is based on experience from similar programs; parametric
models stratify internal databases to simulate environments from many analogous
programs; engineering builds reference similar experience at the unit level; and cost-
estimating relationships (like parametric models) regress algorithms from several
analogous programs. Deciding which of these methodologies (or combination of
methodologies) is the most appropriate for a DFSS project usually depends on avail-
ability of data, which in turn, depends on where the team is in the life cycle or project
scope definition
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:
Analogies
: Cost and schedule are determined based on data from completed
similar efforts. When applying this method, it often is difficult to find analogous
efforts at the total system level. It may be possible, however, to find analo-
gous efforts at the subsystem or lower level computer software configuration
item/computer software component/computer software unit. Furthermore, the
team may be able to find completed efforts that are more or less similar in
complexity. If this is the case, a scaling factor may be applied based on expert
opinion. After an analogous effort has been found, associated data need to be
assessed. It is preferable to use effort rather than cost data; however, if only cost
data are available, these costs must be normalized to the same base year as effort
using current and appropriate inflation indices. As with all methods, the quality
of the estimate is directly proportional to the credibility of the data.
7
See http://www.stsc.hill.af.mil/resources/tech docs/gsam3/chap13.pdf for more details.
8
http://www.stsc.hill.af.mil/resources/tech docs/gsam3/chap13.pdf.
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