What is function point analysis - FPA

One 、 The birth of function point analysis

Traditionally , Software development projects “ Product quantity ” The amount of programming source code that is considered to be written . The code source （SLOC or KLOC）. In the early homogeneous software development environment ,SLOC There is a fairly direct relationship between the number of and the perceived relative size of the software .

However , As technology advances , The software uses mixed languages 、 Reusable modules 、COT Components 、 Utilities 、 Code generators and high-level languages ,SLOC The relationship with the relative size of the software becomes more and more difficult to predict .

Developers need to be able to accurately estimate the workload and cost of delivering software products , And compare different solutions 、 Efficiency and cost effectiveness of technology and tools . But to do that , They need to be able to quantify the scale of the software they are building . stay 1970 Late S ,IBM Of Allan Albrecht Determine the resources required by the software product and the number of functions in the software product 、 There is a fairly predictable relationship between type and complexity .

He developed a method to determine the size of functional requirements , It is called function point analysis . In the past 30 Mid year , The concept of determining the relative size of software by adjusting functional user requirements has made progress , So now the concept has changed to be called “ Function size measurement ” Of ISO standard .

There are four types for function adjustment ISO Method , There are two main categories , Those from Albrecht The original method of （IFPUG Function point analysis and NESMA Function point analysis ） And extensions from his methods （MK II and COSMIC Function adjustment method ）.

Function point analysis （FPA）

Two 、 Introduction to function point analysis

Function point analysis (FPA) It is used to determine the software work product specification ​ Modular technology . since 1970 Since the late s , Function point analysis (FPA) It has been used to evaluate the functions delivered to users according to the external business view of users' functional requirements . Compared with the view of measuring physical implementation or internal technical view , It measures the logical view of the application .

FPA Measure these functional requirements from the following aspects ：

• Business transactions that users can execute using the software （ for example , Query the fault record ）,
• Business data that software can store and access （ for example ,FAULT file ）.

The process of performing function point analysis is called “ Function point count ”, It involves identifying each of these transaction and data components 、 Classification and weighting , The weights are combined to give the function size as the unadjusted function point count .

Function point analysis technology is used to evaluate the functions provided by the software （ Often referred to as “ Function point count ”）,“ The function point ” Is a measure of the size of software functionality .

Once you have the function point count , You can use the result measurement of the software product alone , It can also be combined with other measures , The following indicators can be obtained ：

• The scale of software development （ For example, the software unit to be delivered or worked ）
• Quality indicators （ For example, the number of defects per software unit ）
• Productivity （ For example, the cost per software unit ）
• The performance of （ For example, the human resources of each software unit ）