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CHAPTER 5 SOFTWARE PROJECT PLANNING 131

FIGURE 5.5 Risk Construction
Activity CC Planning Engineering CE Totals
Process-based analysis release
estimation Task Analysis Design Code Test
table
Function

UICF 0.50 2.50 0.40 5.00 n/a 8.40
2DGA 0.75 4.00 0.60 2.00 n/a 7.35
3DGA 0.50 4.00 1.00 3.00 n/a 8.50
CGDF 0.50 3.00 1.00 1.50 n/a 6.00
DBM 0.50 3.00 0.75 1.50 n/a 5.75
PCF 0.25 2.00 0.50 1.50 n/a 4.25
DAM 0.50 2.00 0.50 2.00 n/a 5.00

Totals 0.25 0.25 0.25 3.50 20.50 4.50 16.50 46.00
% effort 1% 1% 1% 8% 45% 10% 36%
CC = customer communication CE = customer evaluation

Costs and effort for each function and software process activity are computed as
the last step. If process-based estimation is performed independently of LOC or FP
estimation, we now have two or three estimates for cost and effort that may be com-
If time permits, use pared and reconciled. If both sets of estimates show reasonable agreement, there is
greater granularity
when specifying tasks good reason to believe that the estimates are reliable. If, on the other hand, the results
in Figure 5.5, such as of these decomposition techniques show little agreement, further investigation and
breaking analysis into analysis must be conducted.
its major tasks and
estimating each 5.6.5 An Example of Process-Based Estimation
separately.
To illustrate the use of process-based estimation, we again consider the CAD soft-
ware introduced in Section 5.6.3. The system configuration and all software func-
tions remain unchanged and are indicated by project scope.
Referring to the completed process-based table shown in Figure 5.5, estimates of
effort (in person-months) for each software engineering activity are provided for each
CAD software function (abbreviated for brevity). The engineering and construction
release activities are subdivided into the major software engineering tasks shown.
Gross estimates of effort are provided for customer communication, planning, and
risk analysis. These are noted in the total row at the bottom of the table. Horizontal
and vertical totals provide an indication of estimated effort required for analysis,
design, code, and test. It should be noted that 53 percent of all effort is expended on
front-end engineering tasks (requirements analysis and design), indicating the rela-
tive importance of this work.
Based on an average burdened labor rate of $8,000 per month, the total estimated
project cost is $368,000 and the estimated effort is 46 person-months. If desired, labor
rates could be associated with each software process activity or software engineer-
ing task and computed separately.