Assignments Portal: CSSE 313 Software Requirements Engineering Assignment

Q: Write a detail note on Function Point Count?

n A function point is a unit of measurement to express the amount of business functionality an information system provides to a user.

n They measure the size of the systems according to the functionality delivered to the user.

n Function point approach is primarily based on logical view of what the user sees and interacts with.

n Since Function Point measure the systems from a functional perspective they are independent of technology, language, development method, or hardware platform used.

n The only variable is the amount of effort needed to deliver a given set of function points.

Where the Function Point Counting is used

The function point is used to accurately define the size and functionality in the work area with intend to estimates which are involved in it.

It is used for measuring the work area.

The main idea of measuring the work area is to identify the size of the project which can be beneficial for requirement analyst what are the complexities involved in measuring the work so as to learn the length of the work. The larger the work area the more time it will take to discover and understand the functionality and it will help the requirement analyst to write the requirement.

For example airline reservation system will contains more functionality than in taking orders in bar.

FP and Estimation: Rule of Thumb

· Function Point support for sizing and estimating is now a standard feature within at least 30 commercial software estimation tools.

· However, the project managers often need quick and informal estimates that can be performed on the spot by using mathematical calculation etc.

· The FP metric has provided a number of useful rules of thumb for quick estimates.

o FPs divided by 150 = Approximate headcount for development software personnel

o FPs divided by 3500 = Approximate headcount for maintenance software personnel

o FPs multiplied by $ 1000 = Approximate software development cost in USA

After you have determined the functionality, size of the project becomes easier to identify the efforts to build the required indented product.

The mathematical formula that is involved in measuring the effort

Efforts = (FP/150) * FP ^0.4

Thus you can say that in 2000 function points work area the efforts involved in person days is (2000/150) * 2000^0.4

Function point are considered useful because of the following characteristics

The more functionality involved in the work area the more efforts and time it will take to gather the requirement.
The greater the amount of functionality the more data it process to meet the requirement from the user perspective.
The data is more understandable and visible it makes more sense to explore the functionality from it.

FUNCTION POINT COUNTING FOR BUSINESS USE CASE:

You can count function points either for a business event that basically identify the business use case individually. It can be more helpful for a requirement analyst we will actually explain the process of counting that will involve in measuring business use cases.

In order to understand the functionality of the business use case you will figure out the requirement that are needed for business use case. It will also help you to count the data elements of the incoming and outgoing data flows as well as the classes that are identified in the use cases.

Function Point Count (FPC)

The function point is a measurement of a particular application or project.

There are four major activities involved in FP counting process for an application.

· Understand the application

· Identify the information processing functions

· Determine the system complexity factors

· Mathematical Computation of FP

Types of Function Point Counts

· Development Project Function Point Count

o This type of count is associated with new development work

· Enhancement Project Function Point Count

o This type of function point count tries to size enhancement projects

· Application Function Point Count

o Application counts are done on existing production applications

How to Use Function Point Count

Function Point Count is used by marketing during proposal stage and by project leaders during project execution. In both cases effort is estimated from the FP Count.

When to Count Function Point

· In theory, there should be no changes in function point count between the end of product design and the end of acceptance testing.

· In practice, there is a big difference. It is during this time of implementation and testing that changes become progressively more expensive to make.

· Very often, users and project managers decide on change requests, features, costs and schedules throughout this time. Function points can be used to quantify these negotiations.

· It is not wise to exchange a 100 function point enhancement for a 100 function point reduction in functionality. The work already expended on the 100 function points to be dropped must also be considered.

What do you do with the function point counts?

To measure the productivity of your staff, your outsourcer or even yourself, and then track it over time;
To estimate project effort and schedule;
To measure your productivity and then compare it to other organizations
To use the data to drive business decisions regarding which applications to retain, retire or redesign.
If you enjoy one or more of the above activities, then you may want to launch a metrics program for your organization.