- Using Functional Metrics to Effectively Manage Outsourcing Arrangements
- Establishing Performance Levels
- Monitoring the Deliverable
- Summary
Monitoring the Deliverable
An organization that chooses to outsource its development activities can use the function point method to manage the cost-effective delivery of the software and the completeness of the functionality being provided. Assuming that a performance baseline has been established and that a cost per function point has been derived, the organization can evaluate future development efforts.
For example, a business analyst would be able to analyze all the business functionality requested and then calculate a function point value. The calculated value is "dollarized" as a cost per function point (cost per unit of work), and the cost for the total system is determined. The resulting value is the cost of the proposed software deliverable presented in terms that the user can understand. Furthermore, the cost per function point can be broken down and displayed by logical business function groups, and the user can readily see the cost for the specific business functions that have been requested. For example, when evaluating the business components of a purchase order system, the cost associated with the processing of a single purchase order could be segmented, and each functionality could be assigned a function point value, as shown in Table 3.
Table 3
Assigning Function Point Values to a Purchase Order System
|
Functionality |
Function Type |
Function Point Value |
|
Purchase order transaction |
Input |
4 function points |
|
Maintained purchase order data |
File |
15 function points |
|
Purchase order status view |
Inquiry |
4 function points |
|
Purchase order report |
Output |
5 function points |
|
Interface to invoicing system |
Interface |
7 function points |
|
Total functional value |
35 function points |
|
|
Cost per function point (baseline data) |
$1,000 |
|
|
Cost to deliver PO functionality |
$35,000 |
|
As the project continues and the scope of work changes based on new requirements, the organization can continue to use function points as a unit of work measure, thereby communicating to the user the exact nature of the scope change and the specific costs associated with that particular scope change (see Table 4).
Table 4
Using Function Points to Estimate the Cost of Scope Changes
|
Change in Scope |
FP Size |
Additional Effort (in Staff Months) |
Additional Cost(in $000) |
Additional Schedule (in Calendar Months) |
|
Add vendor function |
100 |
7 |
100 |
2.0 |
|
Graphical displays |
20 |
1.2 |
20 |
.4 |
|
Invoice interface |
20 |
1.2 |
20 |
.4 |
|
Mandatory changes |
10 |
.6 |
10 |
.2 |
|
Total |
150 |
10 |
$150 |
3 months |