Characteristics of Project Phases
　　项目阶段的特征
　　The completion and approval of one or more deliverables characterizes a project phase. A deliverable is a measurable, verifiable work product such as a specification, feasibility study report, detailed design document, or working prototype. Some deliverables can correspond to the project management process, whereas others are the end products or components of the end products for which the project was conceived. The deliverables, and hence the phases, are part of a generally sequential process designed to ensure proper control of the project and to attain the desired product or service, which is the objective of the project.
　　每个项目阶段都以一个或数个可交付成果的完成为标志。可交付成果是某种有形的、可验证的工作成果，例如，技术规定说明书、可行性研究报告、详细设计文件或可以工作的样品。某些可交付成果可能对应着项目管理过程，而另外一些则是该项目构思时设想的最终产品或产品的组成部分。对于可交付成果，因为相应的阶段是为保证恰当地控制项目和达到项目目的，即取得希望的产品或服务而设计的一般为按顺序首尾衔接的过程的一部分。
　　In any specific project, for reasons of size, complexity, level of risk, and cash flow constraints, phases can be further subdivided into subphases. Each subphase is aligned with one or more specific deliverables for monitoring and control. The majority of these subphase deliverables are related to the primary phase deliverable, and the phases typically take their names from these phase deliverables: requirements, design, build, test, startup, turnover, and others, as appropriate.
　　任何具体的项目，由于规模、复杂程度、风险水平和现金流制约等方面的原因，阶段可以进一步划分为子阶段。为了便于监控，每一个子阶段都要与一个或多个具体的可交付成果联系起来。这些事项的大多数都同基本阶段可交付成果相联系，而且阶段一般都根据这些事项命名：要求说明书、设计、建造、试验、试车、交接和其他，等等，具体视情况而定。
　　A project phase is generally concluded with a review of the work accomplished and the deliverables to determine acceptance, whether extra work is still required, or whether the phase should be considered closed. A management review is often held to reach a decision to start the activities of the next phase without closing the current phase, for example, when the project manager chooses fast tracking as the course of action. Another example is when an information technology company chooses an iterative life cycle where more than one phase of the project might progress simultaneously. Requirements for a module can be gathered and analyzed before the module is designed and constructed. While analysis of a module is being done, the requirements gathering for another module could also start in parallel.
　　项目阶段的结束通常以对完成的工作与可交付成果的审查为标志，目的是确定是否验收，是否仍然需要增加工作，或者是否考虑结束这一阶段。经常要举行管理层审查，以便决定在不结束当前阶段的条件下开始下一阶段的活动，如当项目经理将快速跟进选为行动步骤时，即为如此。某信息技术公司选择可同时绩效的多项目阶段的重复生命期也是这种例子。在收集和分析客户对一个模块的要求和设计与制作这一模块的同时，对第二个模块进行分析，还可以平行地开始收集和分析客户对第三个模块的要求。
　　Similarly, a phase can be closed without the decision to initiate any other phases. For example, the project is completed or the risk is deemed too great for the project to be allowed to continue.
　　同样，在未决定是否启动任何其他阶段时，也可以结束一个阶段。例如，当项目已经完成或者认为风险太大，不允许项目继续下去时，即为如此。
　　Formal phase completion does not include authorizing the subsequent phase. For effective control, each phase is formally initiated to produce a phase-dependent output of the Initiating Process Group, specifying what is allowed and expected for that phase, as shown in Figure 2-3. A phase-end review can be held with the explicit goals of obtaining authorization to close the current phase and to initiate the subsequent one. Sometimes both authorizations can be gained at one review. Phase-end reviews are also called phase exits, phase gates, or kill points.
　　阶段的正式完成不包括核准随后的阶段。为了有效的控制，每一阶段都要正式启动，都要根据该阶段的具体情况提交为该阶段规定允许和预期哪些事项的一项成果。图2-3所表示的就是这种情况。阶段末可以进行一次审查，明确的日的是取得对结束当前阶段并启动下一阶段的核准。有时候，一次审查可以核准两件事。上述阶段末审查往往称为阶段放行口、阶段关卡或验收站。
　　

　　Figure 2-3. Typical Sequence of Phases in a Project Life Cycle
　　
　　图2-3 项目生命期内的典型阶段序列