Abstract: Software scale measurement is an important basis for project management, especially in the early stage. IFPUG FPA（Function Point Analysis）, as a standard software scale measurement method, needs detailed information of software and has complicated computation, hence meets restrictions on the early stage of project application. This paper puts forward a simplified estimation method based on IPFUG FPA to solve the problem. Instead of making use of five objects in the standard method, the new method needs only three objects, including software transaction function, internal data functions and external data functions. Through fixing weighted factor for each object and giving functional point value and range, the method achieves software functional scale. It reduces the difficulty of usage and simplifies the estimation procedure, and the reliability is more than 60% through practical program validation.

Key words: software metrics, Functional Size Measurement （FSM）, Function Point Analysis （FPA）, IFPUG（International Function Point Users&rsquo, Group）, simplified function point

摘要： 软件规模度量是进行软件项目管理的重要依据，在项目早期阶段尤其具有重要意义。IFPUG标准功能点方法需要知道软件详细信息才能完成软件度量，且计算过程复杂，在工程早期应用限制较多。针对这些问题，提出了一种基于IFPUG的简化度量方法，将标准方法的5个对象简化为软件事务功能和内、外部数据功能3个对象，固定每个对象的加权因子，通过给出功能点值及其范围的方法，为简化度量结果提供可靠性参考依据，从而实现软件功能规模简化度量。该简化方法降低了标准功能点方法的使用难度，简化了度量步骤。通过实际项目验证，度量可靠性在60%以上，与其他简化方法相比，结果更加准确。

关键词: 软件度量, 功能规模度量, 功能点分析, IFPUG方法, 简化功能点