ISO/IEC 20968:2002规定了MkII FPA功能尺寸测量方法的定义、惯例和活动。 该方法可用于测量任何软件应用程序的功能大小，该应用程序可以用逻辑事务来描述，每个事务包括输入、处理和输出组件。规模调整规则旨在适用于商业信息系统领域的应用软件，其中每笔交易的处理组件往往由数据存储或检索的考虑因素主导。 该方法可能适用于其他领域的软件，但用户应注意，大小调整规则没有考虑对大小的贡献，例如科学和工程软件中常见的复杂算法，也没有具体考虑实时要求 MK II FPA独立于所采用的项目管理方法和开发方法。 它是对逻辑、业务需求的度量，与它们的实现方式无关。

ISO/IEC 20968:2002 specifies the set of definitions, conventions and activities of the MkII FPA Functional Size Measurement Method. The method can be used to measure the functional size of any software application that can be described in terms of logical transactions, each comprising an input, process and output component. The sizing rules were designed to apply to application software from the domain of business information systems, where the processing component of each transaction tends to be dominated by considerations of the storage or retrieval of data. The method may be applicable to software from other domains, but the user should note that the sizing rules do not take into account contributions to size such as from complex algorithms as typically found in scientific and engineering software, nor do the rules specifically take into account real-time requirements MK II FPA is independent of the project management method to be used and of the development method employed. It is a measure of the logical, business requirements, independent of how they are implemented.