Case Study Analysis: Client X Integration Service

4.1.4. Client “X” Integration Service:
This service has been built to satisfy specific customer’s exact needs. For the purpose of this research the customer’s identity has been hidden and named “X”. This service main functionality is to transfer the data from the temporary database at the client to the customer’s internal system (SAP system).
4.1.4.1. New Service Estimation:
Adjusted Function Point Effort Estimation
As this service has been built from scratch to satisfy special customer’s needs. The different constituent modules and their corresponding function complexity and unadjusted function point are shown in Table 41.the cost factors and their weights are shown in Table 42.The Adjusted function point results are shown in Table 43. As
The graph shows that overestimation exists in both requirements and development phases. However underestimation exists in the rest of the phases. The gap between the estimated and the actual is high in the development and integration phases.

Figure 48:Client “X” Integration new service estimated phased effort distribution relative error

In Figure 48 the relative error among the phases is plotted. The highest relative error is in the integration phase 34.38%, while the lowest relative error is in the testing phase 5.92%.
Table 45 shows the relative error between the adjusted function point and the phased effort distribution ratio. The phased effort distribution approach is more accurate than the adjusted function point as shown in Figure 49.

Table 45: Client ”X” Integration new service adjusted function point relative error compared to the phased effort distribution relative error
Adjusted Function Point Relative Error Phased Effort Distribution Relative Error
14.59% 3.66%

Figure 49: Comparison between the relative error of adjusted function point and the phase effort distribution for the Client “X” Integration
Table 48: Totals service Adjusted Function point estimates and relative error
Estimated Total Effort (Man-Hour) Actual Effort (Man-Hour) Relative Error
192.56 224 14.04%

Figure 50 shows that adjusted function point underestimated the effort of the calculate totals service. Figure 50: Calculate totals service adjusted function point estimated effort compared to the actual effort

Phased Effort Estimation:
Table 49 shows the totals service phased effort with total error relative error 19.08%.
Figure 51 compares the estimated effort to the actual effort in Man-Hour. There is underestimation in all phases of the project. The highest difference is in both design and integration phases.

Table 49: Totals service phased effort ratio results
Phase Estimated Effort ratio (%) Estimated Effort (Man-Hour) Actual Effort (Man-Hour) Relative Error(%) Actual effort ratio(%)
Requirements & Analysis 16 29.00 34 0.00 15.18
Design 15 27.19 42 35.27 18.75
Development 40 72.50 81 10.49 36.16
Testing 22 39.88 45 11.39 20.09
Integration 7 12.69 22 42.33 9.82
Total 100 181.25 224 19.08 100

Figure 51: Calculate Totals service estimated effort distribution compared to the actual effort