Shulou(Shulou.com)06/03 Report--

With the development of information technology and the increase of the scale of the application system, both the builder and the contractor of the system urgently need to build their own data measurement system, in order to strengthen the project process control, improve the birth rate, reduce the production cost and enhance the market competitive advantage.

If an organization wants to build a measurement system that meets its own needs, it must first determine the tools and methods used in measurement, then determine the elements of measurement, that is, which data to measure, and then build a credible measurement database. Finally, analyze the measured data and continuously improve process performance. Through the practice of building a measurement database based on function point analysis in an organization, the basic process of building a measurement system is briefly described as follows:

1. Using function point analysis (FPA).

Function point analysis method has a history of more than 30 years. It is the first function point analysis method for software function scale measurement published by Allan Albrecht, an engineer at IBM, in 1984. Since the establishment of the International function Point user Group (IFPUG) in 1986, the Albrecht method of software function scale measurement has been continuously enhanced, and now it has formed the international standard of function point measurement, that is, ISO/IEC 20926 "IFPUG function scale Measurement". The standard provides a detailed function point measurement method, which identifies the data function (ILF internal logic file and EIF external interface file) and transaction function (EI external input / EQ external query / EO external output) from the user's point of view, and obtains the estimated function points (software scale data) by calculating its complexity and combining 14 adjustment factors. NESMA (Netherlands Software Metrics Association) improved the function point measurement method and formed the international standard ISO/IEC 24570 "function Point Analysis Application definition and Counting Guide". The standard points out that in different demand stages, different estimation parameters are used, such as in the initial stage of the product, the requirements are not fully defined and split, and the software scale can be obtained by counting only the number of ILF and ELF data files in FPA. The calculation rules are as follows: overall UFP (unadjusted function point) = 35xILFC15xELF; after the system requirements are gradually defined, the estimated function point method is used to calculate the function point. The calculation rules are as follows: overall UFP (unadjusted function points) = 10xILF+7xELF+4xEI+5xEO+4xEQ. The calculation rule put forward by Beijing Software cost Evaluation Technology Innovation Alliance (hereinafter referred to as "Alliance") is based on the method of estimating function points in the above two scenarios, through the corresponding adjustment factor, calculate the function points of the adjusted application system.

Function point analysis (FPA) has become an international standard and has been recognized by most countries. this method is a consistent standard, which can meet the application and has acceptable consistency criteria. Since 2013, the Ministry of Industry and Information Technology industry standard "Software Development cost Measurement Standard" and Beijing local standard "Information Project Software Development cost Measurement Standard", more and more domestic software builders and contractors have actively organized to learn FPA methods, and have been widely used in organizational measurement system construction and project implementation.

The construction side of the application system can use the function point analysis method, combined with the industry benchmark data, to estimate the cost estimate of the project, so as to provide a basic basis for the application budget, project bidding or audit; in the process of the construction of the application system, through the collected process data, the contractor can be evaluated and managed to find problems and resolve project risks in time. The application system contractor, using the function point method, only needs to estimate the function points of the project, combined with the industry benchmark data or the organization's own benchmark data, multiplied by the corresponding adjustment factor, the corresponding measurement data can be obtained.

The advantage of using function point analysis is that this method is based on the business point of view to identify data files and basic processes from the perspective of users, without paying attention to how to achieve it technically, which is conducive to users' understanding and application. This method has a high degree of credibility for the initial source data of organizational measurement. In the process of building the organizational measurement system, the function point analysis method is the core competence, which needs to be skillfully mastered.

2. Elements of measurement

If an organization wants to manage the project effectively and improve the performance of the project and organizational process, it must establish an organization-level measurement database to improve the measurement system. As a method of consistent understanding of all parties, function point analysis is conducive to the collection and calculation of measurement data. at present, more and more organizations use this method to obtain the required measurement data.

According to the characteristics of software process improvement, there are many elements for organizations to measure software. the measurement elements related to function point analysis mainly include estimated function points, final function points, function point deviation rate, scale change factor, defect density, production efficiency and so on. Through these effective quantitative data, organizations can improve their own software project measurement system, and gradually form the organization's production efficiency data standard value, quality data standard value and other data. The measurement elements related to function points are shown in Table 1:

Table 1 elements of measurement

After the measurement elements based on function point analysis are determined, organizations can improve or build their own measurement base.

3. Build measurement database.

An organizational measurement database is a collection of multi-project measurement data. In order to build a measurement database, the organization must complete it through the corresponding statistical template or the construction of measurement application system. In addition, the organization also needs to stipulate when and what data will be provided by the project team in the form of a system, and which department will collect, organize and verify it. The collection and management of measurement data must be taken care of by special personnel, leaders should pay attention to it, and should not become a mere formality, otherwise the collected data will be inaccurate and useless, and the purpose of building a measurement database can not be achieved.

The following is explained in detail through a sample construction of an organization's measurement database, as shown in Table 2. In addition to the measurement elements shown in the table, the organization also collects other measurement data, such as earned value analysis data, customer satisfaction, and so on.

Note 1: the initial data of the function point in Table 2 comes from the estimation function point method, and the default project requirements have been clearly defined, otherwise it can be estimated according to the estimated function point method.

Note 2: for the system maintenance tasks after the delivery of the application system, due to the many factors involved, the relevant data need to be measured by an improved function point method, which is not within the scope of this article.

Table 2 Project measurement data

4. Measurement data analysis

The organization obtains the measurement data of each project, and after reaching a certain number of projects, the project data measurement database is formed. The organization has the measurement database is the first step of the work, the key is how to make full use of these data, the organization can analyze the measurement data in different dimensions, find the characteristics and rules of the project, and make dialectical measures. For example, by analyzing the data of the past three years, it is found that the average production efficiency of financial management applications is 11.2 man-hours / function point, that of core business applications is 14.6 man-hours / function points, and that of office automation applications is 9 man-hours / function points, so that when doing similar projects or after-sales maintenance The average production efficiency of this kind of application can be used as the benchmark, combined with the adjusted function points, the workload of the application system can be estimated. In addition, after statistical analysis, the average scale change coefficient of the application system undertaken by the organization within 3 years is 1.2, and the scale change adjustment factor is 1.2 when estimating the function point. The acquisition of these data effectively guides the smooth development of the organization's project, the project implementation process is clear, data collection and statistics are accurate and timely. At the same time, using the data analysis results of the measurement database, we can also evaluate the performance of the case project, or through the comparison of process data, we can find problems in time and reduce the risk of project implementation. At the organizational level, through the results of data analysis, we can provide strong support for the continuous improvement of organizational performance, assessment projects, updating organizational measurement benchmark data and so on.

Therefore, the construction of measurement system based on function point analysis (FPA) is very effective to improve the process control and management ability of organizations and projects. It is believed that with the development of information technology, the release of national standards, and the continuous improvement of function point analysis methods, more and more organizations will inevitably build their own measurement database by understanding, learning and using function point analysis. build an efficient measurement system. (the copyright of this article belongs to Beijing Software cost Evaluation Technology Innovation Alliance, and the source should be indicated when reprinted.)

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