The Project Life Cycle
　　項目生命期
　　Project managers or the organization can divide projects into phases to provide better management control with appropriate links to the ongoing operations of the performing organization. Collectively, these phases are known as the project life cycle. Many organizations identify a specific set of life cycles for use on all of their projects.
　　項目經理或組織可以把每一個項目劃分成若干個階段，以便有效地進行管理控制，并與實施該項目組織的日常運作聯(lián)系起來。這些項目階段合在一起稱為項目生命期。許多組織識別出一套具體的生命期供其所有的項目使用。
　　Characteristics of the Project Life Cycle
　　項目生命期的特征
　　The project life cycle defines the phases that connect the beginning of a project to its end. For example, when an organization identifies an opportunity to which it would like to respond, it will often authorize a feasibility study to decide whether it should undertake the project. The project life cycle definition can help the project manager clarify whether to treat the feasibility study as the first project phase or as a separate, stand-alone project. Where the outcome of such a preliminary effort is not clearly identifiable, it is best to treat such efforts as a separate project.
　　項目生命期確定了將項目的開始和結束連接起來的階段。例如，當某個組織發(fā)現(xiàn)一個可以考慮和利用的機會時，它通常會責成有關人員進行可行性研究，以決定該項目是否值得立項。項目生命期的定義有助于項目經理弄清是否應將該項可行性研究視為項目的第一個階段，或者將其當做一個單獨的項目。當這種初步努力的結果無法識別清楚時，最好將其當做單獨的項目進行處理。
　　The transition from one phase to another within a project's life cycle generally involves, and is usually defined by, some form of technical transfer or handoff. Deliverables from one phase are usually reviewed for completeness and accuracy and approved before work starts on the next phase. However, it is not uncommon for a phase to begin prior to the approval of the previous phase's deliverables, when the risks involved are deemed acceptable. This practice of overlapping phases, normally done in sequence, is an example of the application of the schedule compression technique called fast tracking.
　　從項目生命期的一個階段轉到另一階段通常是某種形式的技術交接，這種階段轉移通常也由這種技術交接確定。前一階段產生的可交付成果通常要接受是否已經完成和準確的審查，在驗收之后才能開始下一階段的工作。但是，如果認為所涉及的風險是可以接受的話，后一階段可以在前一階段可交付成果通過驗收之前開始。通常這種將按照先后順序完成的兩個階段重疊的做法，是應用所謂快速跟進進度壓縮技術的一個例子。
　　There is no single best way to define an ideal project life cycle. Some organizations have established policies that standardize all projects with a single life cycle, while others allow the project management team to choose the most appropriate life cycle for the team's project. Further, industry common practices will often lead to the use of a preferred life cycle within that industry.
　　目前沒有確定項目生命期的惟一最好辦法。某些組織的既定方針是用一個項目生命期作為標準的方式處理所有的項目，而另外一些單位則允許項目管理團隊為其項目選擇最適合的項目生命期。另外，行業(yè)的通用做法經常造成本行業(yè)內部使用某種約定俗成的項目生命期。項目生命期的定義還將確定項目開始與結束時的哪些過渡行動應包括在項目范圍之內，哪些則不應包括在內。這樣，就可以用項目生命期的定義把項目和項目實施組織持續(xù)的日常運作業(yè)務聯(lián)系在一起。
　　Project life cycles generally define:
　　項目生命期通常規(guī)定：
　　What technical work to do in each phase （for example, in which phase should the architect's work be performed?）
　　項目的各個階段應當從事何種技術工作（例如，建筑師的工作應放在項目的哪個階段完成）。
　　When the deliverables are to be generated in each phase and how each deliverable is reviewed, verified, and validated
　　項目各階段可交付成果應何時生成，以及如何審查、核實和確認。
　　Who is involved in each phase （for example, concurrent engineering requires that the implementers be involved with requirements and design）
　　項目各階段由哪些人員參與（例如，并行工程要求實施人員參與制定要求說明書和設計）。
　　How to control and approve each phase.
　　如何控制和批準項目各個階段。
　　Project life cycle descriptions can be very general or very detailed. Highly detailed descriptions of life cycles can include forms, charts, and checklists to provide structure and control.
　　說明項目生命期時可以十分籠統(tǒng)，也可以非常詳細。非常詳細的說明可以包括許多表格、圖表和核對表，使其條理清楚，便于控制。
　　Most project life cycles share a number of common characteristics:
　　大多數(shù)項目生命期的說明具有若干共同特點：
　　Phases are generally sequential and are usually defined by some form of technical information transfer or technical component handoff.
　　項目階段一般按順序首尾銜接，通常根據(jù)某種形式的技術信息傳遞或技術部件交接來確定。
　　Cost and staffing levels are low at the start, peak during the intermediate phases, and drop rapidly as the project draws to a conclusion. Figure 2-1 illustrates this pattern.
　　人力投入和費用，開始時低，隨之增高，在項目接近收尾時迅速下降。這種模式如圖2-1所示。


　　Figure 2-2. Stakeholders' Influence Over Time

　　圖2-2利害關系者影響隨著時間的變化

　　The level of uncertainty is highest and, hence, risk of failing to achieve the objectives is greatest at the start of the project. The certainty of completion generally gets progressively better as the project continues.
　　項目開始時，成功地完成項目的可能性最低，因此風險和不確定性最高。隨著項目繼續(xù)績效，成功地完成項目的可能性通常都逐漸上升。
　　The ability of the stakeholders to influence the final characteristics of the project's product and the final cost of the project is highest at the start, and gets progressively lower as the project continues. Figure 2-2 illustrates this. A major contributor to this phenomenon is that the cost of changes and correcting errors generally increases as the project continues.
　　項目開始時，項目利害關系者對項目產品最后特點和項目最后成本的影響力最強，而隨著項目的績效，這種影響逐步減弱。圖2-2形象地說明了這一點。造成這種現(xiàn)象的主要原因是隨著項目的績效，變更計劃和糾正失誤的代價通常與日俱增。　　


　　Figure 2-2. Stakeholders' Influence Over Time

　　圖2-2利害關系者影響隨著時間的變化

　　Although many project life cycles have similar phase names with similar deliverables, few life cycles are identical. Some can have four or five phases, but others may have nine or more. Single application areas are known to have significant variations. One organization's software development life cycle can have a single design phase, while another can have separate phases for architectural and detailed design. Subprojects can also have distinct project life cycles. For example, an architectural firm hired to design a new office building is first involved in the owner's definition phase while doing the design, and in the owner's implementation phase while supporting the construction effort. The architect's design project, however, will have its own series of phases from conceptual development, through definition and implementation, to closure. The architect can even treat designing the facility and supporting the construction as separate projects, each with its own set of phases.
　　盡管許多項目生命期具有彼此相似的階段名稱，所要求的可交付成果名稱也極其相似，但其內容絕少雷同。某些項目有4個或5個階段，但另一些項目可多達9個階段以上。即使在某單一應用領域內，也會有很大差別，如一個組織的軟件開發(fā)生命期可能只有一個設計階段，而另一個組織卻可能將其分為功能設計和詳細設計兩個單獨的階段。項目內的子項目也可以有明顯的項目生命期。例如，一家建筑師事務所受雇為他人設計新辦公樓時，首先在設計時參與了業(yè)主的設計要求制定階段，隨后又在協(xié)助施工時參與了業(yè)主的實施階段，協(xié)助施工。但建筑師本身的設計項目也有自己的一系列階段，包括項目構思、要求制定、實施，直至項目收尾。這位建筑師甚至可以把辦公樓的設計和對施工的協(xié)助視為兩個不同的項目，分別包括各自的明顯階段。