Earned value management (EVM), or earned value project/performance management (EVPM) is a project management technique for measuring project performance and progress in an objective manner.
挣值管理（EVM）或挣值项目/绩效管理（EVPM）是一种以客观方式衡量项目绩效和进度的项目管理技术。
Overview
Earned value management is a project management technique for measuring project performance and progress. It has the ability to combine measurements of the project management triangle: scope, time, and costs.
挣值管理是一种用于衡量项目绩效和进度的项目管理技术。它能够结合项目管理三角形的测量：范围，时间和成本。
In a single integrated system, earned value management is able to provide accurate forecasts of project performance problems, which is an important contribution for project management.
在一个单一的综合系统中，挣值管理能够提供项目绩效问题的准确预测，这对项目管理是一项重要贡献。
Early EVM research showed that the areas of planning and control are significantly impacted by its use; and similarly, using the methodology improves both scope definition as well as the analysis of overall project performance. More recent research studies have shown that the principles of EVM are positive predictors of project success.[1] Popularity of EVM has grown in recent years beyond government contracting, a sector in which its importance continues to rise[2] (e.g. recent new DFARSrules[3]), in part because EVM can also surface in and help substantiate contract disputes.[4]
早期的EVM研究表明，规划和控制领域受到其使用的重大影响; 同样，使用该方法可以改进范围定义以及整体项目绩效分析。最近的研究表明，EVM的原则是项目成功的积极预测因素。近年来，EVM的受欢迎程度超过了政府合同，其重要性持续上升（例如最近新的DFARS规则），部分原因在于EVM也可以出现并帮助证实合同纠纷。
Essential features of any EVM implementation include:
任何EVM实施的基本特征包括：
- A project plan that identifies work to be accomplished
一个项目计划标识工作完成 - A valuation of planned work, called planned value (PV) or budgeted cost of work scheduled (BCWS)
计划工作的估价，称为计划价值（PV）或预定工作的预算成本（BCWS） - Pre-defined "earning rules" (also called metrics) to quantify the accomplishment of work, called earned value (EV) or budgeted cost of work performed (BCWP)
预定义的“收入规则”（也称为度量）来量化完成工作，称为挣值（EV）或预算工作成本（BCWP）
EVM implementations for large or complex projects include many more features, such as indicators and forecasts of cost performance (over budget or under budget) and schedule performance (behind schedule or ahead of schedule). However, the most basic requirement of an EVM system is that it quantifies progress using PV and EV.
针对大型项目或复杂项目的EVM实施包含更多功能，例如成本绩效（超出预算或预算不足）和计划绩效（落后于计划或提前计划）的指标和预测。然而，EVM系统最基本的要求是，它使用PV和EV量化进度。
Application example
应用实例
Project A has been approved for a duration of one year and with the budget of X. It was also planned that the project spends 50% of the approved budget in the first six months. If now, six months after the start of the project, a project manager would report that he has spent 50% of the budget, one can initially think, that the project is perfectly on plan. However, in reality the provided information is not sufficient to come to such a conclusion. The project can spend 50% of the budget, whilst finishing only 25% of the work, which would mean the project is not doing well; or the project can spend 50% of the budget, whilst completing 75% of the work, which would mean that project is doing better than planned. EVM is meant to address such and similar issues.
项目A获得核准的期限为一年，预算为X.还计划在头六个月内将该项目用于核定预算的50％。如果现在，在项目开始六个月后，项目经理会报告说，他已经花费了50％的预算，可以初步认为，该项目完全符合计划。但是，实际上所提供的信息不足以得出这样的结论。该项目可以花费50％的预算，而只完成25％的工作，这意味着项目进展不顺利; 或者该项目可以花费50％的预算，同时完成75％的工作，这意味着该项目比计划好。EVM旨在解决这些和类似的问题。
History
历史
EVM emerged as a financial analysis specialty in United States Government programs in the 1960s, but it has since become a significant branch of project management and cost engineering. Project management research investigating the contribution of EVM to project success suggests a moderately strong positive relationship.[5] Implementations of EVM can be scaled to fit projects of all sizes and complexities.
EVM 在20世纪60年代成为美国政府项目的财务分析专业，但它已成为项目管理和成本工程的重要分支。项目管理研究调查了EVM对项目成功的贡献，表明了一个适度强烈的积极关系。[5] EVM的实施可以扩展到适合各种规模和复杂性的项目。
The genesis of EVM occurred in industrial manufacturing at the turn of the 20th century, based largely on the principle of "earned time" popularized by Frank and Lillian Gilbreth, but the concept took root in the United States Department of Defensein the 1960s. The original concept was called PERT/COST, but it was considered overly burdensome (not very adaptable) by contractors who were mandated to use it, and many variations of it began to proliferate among various procurement programs. In 1967, the DoD established a criterion-based approach, using a set of 35 criteria, called the Cost/Schedule Control Systems Criteria (C/SCSC). In the 1970s and early 1980s, a subculture of C/SCSC analysis grew, but the technique was often ignored or even actively resisted by project managers in both government and industry. C/SCSC was often considered a financial control tool that could be delegated to analytical specialists.
EVM的起源发生在20世纪初的工业制造业，主要基于弗兰克和莉莲吉尔布雷斯推广的“赚钱时间”的原则，但是这个概念在20世纪60年代扎根于美国国防部。最初的概念被称为PERT / COST，但被授权使用它的承包商认为它过于繁重（不太适应），并且它的许多变体开始在各种采购计划中激增。1967年，美国国防部建立了基于标准的方法，使用一套称为成本/进度控制系统标准（C / SCSC）的35个标准。在20世纪70年代和80年代初，亚文化的C / SCSC分析增长了，但这项技术往往被政府和工业界的项目经理忽视甚至积极抵制。C / SCSC通常被认为是可以委托给分析专家的财务控制工具。
In 1979, EVM was introduced to the architecture and engineering industry in a "Public Works Magazine" article by David Burstein, a project manager with a national engineering firm. This technique has been taught ever since as part of the project management training program presented by PSMJ Resources, an international training and consulting firm that specializes in the engineering and architecture industry.
1979年，EVM在一家国家工程公司的项目经理David Burstein的“公共工程杂志”文章中介绍给建筑和工程行业。这项技术自从作为PSMJ Resources提供的项目管理培训计划的一部分开始就已经被教授，PSMJ Resources是一家专门从事工程和建筑行业的国际培训和咨询公司。
In the late 1980s and early 1990s, EVM emerged as a project management methodology to be understood and used by managers and executives, not just EVM specialists. In 1989, EVM leadership was elevated to the Undersecretary of Defense for Acquisition, thus making EVM an element of program management and procurement. In 1991, Secretary of Defense Dick Cheney canceled the Navy A-12 Avenger II Program because of performance problems detected by EVM. This demonstrated conclusively that EVM mattered to secretary-level leadership. In the 1990s, many U.S. Government regulations were eliminated or streamlined. However, EVM not only survived the acquisition reform movement, but became strongly associated with the acquisition reform movement itself. Most notably, from 1995 to 1998, ownership of EVM criteria (reduced to 32) was transferred to industry by adoption of ANSI EIA 748-A standard.[6]
在20世纪80年代末和20世纪90年代初，EVM成为项目管理方法论，以供管理人员和管理人员理解和使用，而不仅仅是EVM专家。1989年，EVM领导层被提升为采购国防部副部长，从而使EVM成为项目管理和采购的一部分。1991年，国防部长 迪克切尼取消了海军A-12复仇者II计划，因为EVM发现了性能问题。这充分证明了EVM与秘书级领导层的关系。在20世纪90年代，许多美国政府的规定被淘汰或精简。然而，EVM不仅在收购改革运动中幸存下来，而且与收购改革运动本身密切相关。最值得注意的是，从1995年到1998年，通过采用ANSI EIA 748-A标准将EVM标准（减少到32个）的所有权转移给了工业。[6]
The use of EVM expanded beyond the U.S. Department of Defense. It was adopted by the National Aeronautics and Space Administration, United States Department of Energy and other technology-related agencies. Many industrialized nations also began to utilize EVM in their own procurement programs.
EVM的使用扩展到美国国防部之外。它被美国国家航空航天局，美国能源部和其他技术相关机构采用。许多工业化国家也开始在自己的采购项目中使用EVM。
An overview of EVM was included in the Project Management Institute's first PMBOK Guide in 1987 and was expanded in subsequent editions. In the most recent edition of the PMBOK guide, EVM is listed among the general tools and techniques for processes to control project costs.[7]
项目管理协会在1987年的第一份PMBOK指南中包含了EVM的概述，并在随后的版本中进行了扩展。在最新版的PMBOK指南中，EVM被列为控制项目成本过程的一般工具和技术。[7]
The construction industry was an early commercial adopter of EVM. Closer integration of EVM with the practice of project management accelerated in the 1990s. In 1999, the Performance Management Association merged with the Project Management Institute (PMI) to become PMI’s first college, the College of Performance Management. The United States Office of Management and Budget began to mandate the use of EVM across all government agencies, and, for the first time, for certain internally managed projects (not just for contractors). EVM also received greater attention by publicly traded companies in response to the Sarbanes-Oxley Act of 2002.
建筑业是EVM的早期商业采用者。20世纪90年代，EVM与项目管理实践更加紧密地结合在一起。1999年，绩效管理协会与项目管理学院（PMI）合并成为PMI的第一所学院 - 绩效管理学院。在管理和预算的美国办事处开始在所有政府机构要求使用EVM的，而且，对于第一次，对于某些内部托管项目（不只是合同工）。上市公司为响应2002年萨班斯 - 奥克斯利法案而受到上市公司的更多关注。
In Australia EVM has been codified as standards AS 4817-2003 and AS 4817-2006.
在澳大利亚，EVM已被编入标准AS 4817-2003和AS 4817-2006。
Project tracking
项目跟踪
It is helpful to see an example of project tracking that does not include earned value performance management. Consider a project that has been planned in detail, including a time-phased spend plan for all elements of work. Figure 1 shows the cumulative budget (cost) for this project as a function of time (the blue line, labeled PV). It also shows the cumulative actual cost of the project (red line, labeled AC) through week 8. To those unfamiliar with EVM, it might appear that this project was over budget through week 4 and then under budget from week 6 through week 8. However, what is missing from this chart is any understanding of how much work has been accomplished during the project. If the project was actually completed at week 8, then the project would actually be well under budget and well ahead of schedule. If, on the other hand, the project is only 10% complete at week 8, the project is significantly over budget and behind schedule. A method is needed to measure technical performance objectively and quantitatively, and that is what EVM accomplishes.
查看不包括挣值性能管理的项目跟踪示例很有帮助。考虑一个已经详细规划的项目，包括针对所有工作要素的分阶段支出计划。图1显示了该项目的累计预算（成本）与时间的函数关系（蓝线，标记为PV）。它还显示了项目（红线，标为AC）在第8周的累计实际成本。对于那些不熟悉EVM的人来说，可能看起来这个项目在第4周超出预算，然后在第6周到第8周的预算范围内。然而，这张图表中缺少的是对项目期间已经完成了多少工作的任何理解。如果该项目在第8周实际完成，那么该项目实际上将远远低于预算，并且提前完成。另一方面，如果该项目在第8周时只完成了10％，那么该项目明显超出预算并落后于计划。需要一种方法客观和定量地衡量技术性能，这就是EVM完成的。
With EVM
使用EVM
Consider the same project, except this time the project plan includes pre-defined methods of quantifying the accomplishment of work. At the end of each week, the project manageridentifies every detailed element of work that has been completed, and sums the EV for each of these completed elements. Earned value may be accumulated monthly, weekly, or as progress is made.
考虑同一个项目，除了这次项目计划包括量化工作成果的预定义方法。在每周结束时，项目经理确定已完成的每项详细工作要素，并对这些已完成要素中的每一个进行EV评估。获得的价值可能会每月，每周或按进度累计。
Earned value (EV)
挣值（EV）
Figure 2 shows the EV curve (in green) along with the PV curve from Figure 1. The chart indicates that technical performance (i.e. progress) started more rapidly than planned, but slowed significantly and fell behind schedule at week 7 and 8. This chart illustrates the schedule performance aspect of EVM. It is complementary to critical path or critical chain schedule management.
图2显示了图1中的EV曲线（绿色）以及PV曲线。该图表明技术性能（即进度）比计划开始更快，但在第7周和第8周显着下降并落后于计划。此图表阐述了EVM的进度表现方面。它对关键路径或关键链表进行管理是相辅相成的。
Figure 3 shows the same EV curve (green) with the actual cost data from Figure 1 (in red). It can be seen that the project was actually under budget, relative to the amount of work accomplished, since the start of the project. This is a much better conclusion than might be derived from Figure 1.
图3显示了与图1中的实际成本数据（红色）相同的EV曲线（绿色）。可以看出，自项目开始以来，该项目实际上处于预算之内，相对于完成的工作量而言。这是比图1更好的结论。
Figure 4 shows all three curves together – which is a typical EVM line chart. The best way to read these three-line charts is to identify the EV curve first, then compare it to PV (for schedule performance) and AC (for cost performance). It can be seen from this illustration that a true understanding of cost performance and schedule performance relies first on measuring technical performance objectively. This is the foundational principle of EVM.
图4显示了所有三条曲线 - 这是一个典型的EVM折线图。阅读这些三线图表的最好方法是首先确定EV曲线，然后将其与PV（用于进度表现）和AC（用于成本表现）进行比较。从这个例子可以看出，对成本绩效和进度绩效的真正理解首先依赖于客观地衡量技术绩效。这是EVM 的基本原理。
Scaling EVM from simple to advanced implementations
将EVM从简单的扩展到高级实现
The foundational principle of EVM, mentioned above, does not depend on the size or complexity of the project. However, the implementations of EVM can vary significantly depending on the circumstances. In many cases, organizations establish an all-or-nothing threshold; projects above the threshold require a full-featured (complex) EVM system and projects below the threshold are exempted. Another approach that is gaining favor is to scale EVM implementation according to the project at hand and skill level of the project team.
上述 EVM 的基本原理并不取决于项目的规模和复杂程度。但是，EVM 的实现可能因环境而异。在很多情况下，组织建立一个全或无的门槛; 高于门限的项目需要全功能（复杂）EVM系统，低于门限的项目可以免除。获得青睐的另一种方法是根据项目团队的项目和技能水平来扩展EVM实施。
Simple implementations (emphasizing only technical performance)
简单的实现（只强调技术性能）
There are many more small and simple projects than there are large and complex ones, yet historically only the largest and most complex have enjoyed the benefits of EVM. Still, lightweight implementations of EVM are achievable by any person who has basic spreadsheet skills. In fact, spreadsheet implementations are an excellent way to learn basic EVM skills.
还有更多的小而简单的项目比大而复杂的项目要多，但是历史上只有最大和最复杂的才能享受EVM的好处。尽管如此，任何具有基本电子表格技能的人都可以实现轻量级的EVM实现。事实上，电子表格实施是学习基本EVM技能的绝佳方式。
The first step is to define the work. This is typically done in a hierarchical arrangement called a work breakdown structure (WBS) although the simplest projects may use a simple list of tasks. In either case, it is important that the WBS or list be comprehensive. It is also important that the elements be mutually exclusive, so that work is easily categorized in one and only one element of work. The most detailed elements of a WBS hierarchy (or the items in a list) are called activities (or tasks).
该第一步是定义工作。这通常是在称为工作分解结构（WBS）的分层结构中完成的，尽管最简单的项目可能使用简单的任务列表。无论是哪种情况，重要的是WBS或清单要全面。元素互相排斥也很重要，以便工作很容易被分类到一个且仅有的一个工作元素中。WBS层次结构中最详细的元素（或列表中的项目）称为活动（或任务）。
The second step is to assign a value, called planned value (PV), to each activity. For large projects, PV is almost always an allocation of the total project budget, and may be in units of currency (e.g. dollar, euro or naira) or in labor hours, or both. However, in very simple projects, each activity may be assigned a weighted “point value" which might not be a budget number. Assigning weighted values and achieving consensus on all PV quantities yields an important benefit of EVM, because it exposes misunderstandings and miscommunications about the scope of the project, and resolving these differences should always occur as early as possible. Some terminal elements can not be known (planned) in great detail in advance, and that is expected, because they can be further refined at a later time.
第二步骤是要分配的值，称为计划值（PV），每个活性。对于大型项目，光伏几乎总是项目总预算的分配，并且可能以货币单位（例如美元，欧元或奈拉）或劳动时间或两者兼而有之。然而，在非常简单的项目中，每项活动都可能被赋予一个加权的“点值”，这可能不是预算编号。对所有光伏数量分配加权值并达成一致意见会产生EVM的一个重要好处，因为它暴露了误解和错误交流项目的范围和解决这些差异应该尽可能早地发生，一些终端要素事先不能被详细了解（计划），这是可以预期的，因为它们可以在以后进一步细化。
The third step is to define "earning rules" for each activity. The simplest method is to apply just one earning rule, such as the 0/100 rule, to all activities. Using the 0/100 rule, no credit is earned for an element of work until it is finished. A related rule is called the 50/50 rule, which means 50% credit is earned when an element of work is started, and the remaining 50% is earned upon completion. Other fixed earning rules such as a 25/75 rule or 20/80 rule are gaining favor, because they assign more weight to finishing work than for starting it, but they also motivate the project team to identify when an element of work is started, which can improve awareness of work-in-progress. These simple earning rules work well for small or simple projects because generally each activity tends to be fairly short in duration.
在第三步是为每项活动定义“收入规则”。最简单的方法是仅对所有活动应用一个收益规则，例如0/100规则。使用0/100规则，在完成工作之前不会为其获得功劳。一个相关的规则被称为50/50规则，这意味着当工作要素开始时获得50％的信用，剩余的50％在完成时获得。其他固定收入规则（如25/75规则或20/80规则）正在受到青睐，因为他们为完成工作分配了比开始工作更多的重量，但他们也激励项目团队确定何时开始工作元素，这可以提高对在制品的认识。这些简单的收入规则适用于小型或简单的项目，因为通常每个活动的持续时间都相当短。
These initial three steps define the minimal amount of planning for simplified EVM. The final step is to execute the project according to the plan and measure progress. When activities are started or finished, EV is accumulated according to the earning rule. This is typically done at regular intervals (e.g. weekly or monthly), but there is no reason why EV cannot be accumulated in near real-time, when work elements are started/completed. In fact, waiting to update EV only once per month (simply because that is when cost data are available) only detracts from a primary benefit of using EVM, which is to create a technical performance scoreboard for the project team.
这些最初的三个步骤定义了简化EVM的最小规划数量。在最后的步骤是按计划来执行该项目，并衡量进展情况。当活动开始或结束时，EV根据收入规则进行累计。这通常是定期（例如每周或每月）完成的，但当工作要素开始/完成时，没有理由不能近乎实时地积累EV。事实上，每月只有一次EV更新（仅仅是因为有成本数据时），这只会降低使用EVM的主要优势，即为项目团队创建技术性能记分牌。
In a lightweight implementation such as described here, the project manager has not accumulated cost nor defined a detailed project schedule network (i.e. using a critical path or critical chain methodology). While such omissions are inappropriate for managing large projects, they are a common and reasonable occurrence in many very small or simple projects. Any project can benefit from using EV alone as a real-time score of progress. One useful result of this very simple approach (without schedule models and actual cost accumulation) is to compare EV curves of similar projects, as illustrated in Figure 5. In this example, the progress of three residential construction projects are compared by aligning the starting dates. If these three home construction projects were measured with the same PV valuations, the relative schedule performance of the projects can be easily compared.
在如此处所述的轻量级实施中，项目经理没有累计成本，也没有定义详细的项目进度网络（即使用关键路径或关键链方法）。虽然这种疏忽不适合管理大型项目，但在许多非常小或简单的项目中，这是一种常见而合理的事件。任何项目都可以单独使用EV作为实时进度评分。这种非常简单的方法（没有时间表模型和实际成本积累）的一个有用结果是比较类似项目的EV曲线，如图5所示。在这个例子中，通过调整起始日期来比较三个住宅建设项目的进度。如果这三个房屋建筑项目是用相同的光伏估值来衡量的，那么项目的相对时间表性能可以很容易地进行比较。
Intermediate implementations (integrating technical and schedule performance)
中间实现（整合技术和计划表现）
In many projects, schedule performance (completing the work on time) is equal in importance to technical performance. For example, some new product development projects place a high premium on finishing quickly. It is not that cost is unimportant, but finishing the work later than a competitor may cost a great deal more in lost market share. It is likely that these kinds of projects will not use the lightweight version of EVM described in the previous section, because there is no planned timescale for measuring schedule performance. A second layer of EVM skill can be very helpful in managing the schedule performance of these “intermediate” projects. The project manager may employ a critical path or critical chain to build a project schedule model. As in the lightweight implementation, the project manager must define the work comprehensively, typically in a WBS hierarchy. He/she will construct a project schedule model that describes the precedence links between elements of work. This schedule model can then be used to develop the PV curve (or baseline), as shown in Figure 2.
在许多项目中，时间安排表现（按时完成工作）对技术表现具有同等重要性。例如，一些新产品开发项目很快就完成了高级加工。并不是说成本并不重要，但是晚于竞争对手完成工作可能会损失更多的市场份额。这些类型的项目可能不会使用上一节中介绍的轻量级EVM版本，因为没有计划时间表的计划时间表。第二层EVM技能对管理这些“中间”项目的进度表现非常有帮助。项目经理可以采用关键路径或关键链来构建项目进度模型。与轻量级实施一样，项目经理必须全面定义工作，通常以WBS层次结构进行。他/她将构建一个描述工作要素之间优先关系的项目进度模型。这个时间表模型可以用来开发PV曲线（或基线），如图2所示。
It should be noted that measuring schedule performance using EVM does not replace the need to understand schedule performance versus the project's schedule model (precedence network). However, EVM schedule performance, as illustrated in Figure 2 provides an additional indicator — one that can be communicated in a single chart. Although it is theoretically possible that detailed schedule analysis will yield different conclusions than broad schedule analysis, in practice there tends to be a high correlation between the two. Although EVM schedule measurements are not necessarily conclusive, they provide useful diagnostic information.
应该指出，使用EVM测量进度表的性能并不能取代理解与项目进度表模型（优先网络）相比进度表现的需要。但是，如图2所示，EVM的时间表性能提供了额外的指标 - 可以在单个图表中进行沟通。尽管理论上可能的是详细的进度分析将得出与广泛进度分析不同的结论，但实际上这两者之间往往存在高度相关性。尽管EVM时间表测量结果不一定是确凿的，但它们提供了有用的诊断信息。
Although such intermediate implementations do not require units of currency (e.g. dollars), it is common practice to use budgeted dollars as the scale for PV and EV. It is also common practice to track labor hours in parallel with currency. The following EVM formulas are for schedule management, and do not require accumulation of actual cost (AC). This is important because it is common in small and intermediate size projects for true costs to be unknown or unavailable.
虽然这种中间实施不需要货币单位（如美元），但通常使用预算美元作为光伏和电动车的规模。追踪与货币并行的劳动时间也是常见的做法。以下EVM公式用于进度管理，并且不需要累计实际成本（AC）。这很重要，因为在中小规模项目中，真实成本未知或不可用的情况很常见。
- Schedule variance (SV)
时间表差异（SV） 
- SV greater than 0 is good (ahead of schedule). The SV will be 0 at project completion because then all of the planned values will have been earned.
SV大于0是好的（提前计划）。在项目完成时，SV将为0，因为那时所有的计划值都将获得。
However, Schedule Variance (SV) measured through EVM method is indicative only. To know whether a project is really behind or ahead of schedule (on time completion), Project Manager has to perform critical path analysis based on precedence and inter-dependencies of the project activities.
但是，通过EVM方法测量的时间安排方差（SV）仅供参考。要知道项目是否落后或提前（按时完成），项目经理必须根据项目活动的优先级和相互依赖性进行关键路径分析。
- Schedule performance index (SPI)
计划绩效指数（SPI） - SPI greater than 1 is favourable (ahead of schedule).
SPI大于1是有利的（提前计划）。
Making earned value schedule metrics concordant with the CPM schedule
获得的价值计划指标与CPM计划一致
The actual critical path is ultimately the determining factor of every project's duration. Because earned value schedule metrics take no account of critical path data, big budget activities that are not on the critical path have the potential to dwarf the impact of performing small budget critical path activities. This can lead to "gaming" the SV and SPI metrics by ignoring critical path activities in favor of big budget activities that may have lots of float. This can sometimes even lead to performing activities out-of-sequence just to improve the schedule tracking metrics, which can cause major problems with quality.
实际的关键路径最终是每个项目持续时间的决定因素。由于挣值计划指标不考虑关键路径数据，因此不在关键路径上的大型预算活动有可能使执行小型预算关键路径活动的影响变得更小。这可能导致“游戏”SV和SPI指标，忽略关键路径活动而偏向可能有很多浮动的大型预算活动。这有时甚至会导致不按顺序执行活动，以改进计划跟踪指标，这可能会导致质量出现重大问题。
A simple two-step process has been suggested to fix this:
有人提出了一个简单的两步过程来解决这个问题：
- Create a second earned value baseline strictly for schedule, with the weighted activities and milestones on the as-late-as-possible dates of the backward pass of the critical path algorithm, where there is no float.
严格按计划创建第二个挣值基线，并在关键路径算法的后向传递的尽可能晚的日期加权的活动和里程碑，其中没有浮动。 - Allow earned value credit for schedule metrics to be taken no earlier than the reporting period during which the activity is scheduled unless it is on the project's current critical path.
在计划活动计划的报告期间内，除非计划活动目前处于关键路径，否则可以获取计划指标的获得值贷记。
In this way, the distorting aspect of float would be eliminated. There would be no benefit to performing a non-critical activity with lots of float until it is due in proper sequence. Also, an activity would not generate a negative schedule variance until it had used up its float. Under this method, one way of gaming the schedule metrics would be eliminated. The only way of generating a positive schedule variance (or SPI over 1.0) would be by completing work on the current critical path ahead of schedule, which is in fact the only way for a project to get ahead of schedule.
这样，浮动的扭曲方面就会被消除。执行具有大量浮动的非关键活动，直到按正确顺序到期为止没有任何好处。此外，一项活动在用完浮动之前不会产生负面的进度变化。在这种方法下，消除时间表度量的一种方式将被消除。产生积极的进度差异（或SPI超过1.0）的唯一方法是通过提前完成当前关键路径上的工作，这实际上是提前完成项目的唯一途径。
Advanced implementations (integrating cost, schedule and technical performance)
高级实施（集成成本，时间表和技术性能）
In addition to managing technical and schedule performance, large and complex projects require that cost performance be monitored and reviewed at regular intervals. To measure cost performance, planned value (or BCWS - Budgeted Cost of Work Scheduled) and earned value (or BCWP - Budgeted Cost of Work Performed) must be in units of currency (the same units that actual costs are measured.) In large implementations, the planned value curve is commonly called a Performance Measurement Baseline (PMB) and may be arranged in control accounts, summary-level planning packages, planning packages and work packages. In large projects, establishing control accounts is the primary method of delegating responsibility and authority to various parts of the performing organization. Control accounts are cells of a responsibility assignment (RACI) matrix, which is the intersection of the project WBS and the organizational breakdown structure (OBS). Control accounts are assigned to Control Account Managers (CAMs). Large projects require more elaborate processes for controlling baseline revisions, more thorough integration with subcontractor EVM systems, and more elaborate management of procured materials.
除了管理技术和进度表现外，大型复杂项目还需要定期监控和审查成本绩效。为了衡量成本绩效，计划价值（或BCWS - 计划工作的预算成本）和挣值（或BCWP - 执行工作的预算成本）必须以货币为单位（与测量实际成本相同的单位）。 ，计划价值曲线通常称为绩效评估基准（PMB），可以安排在控制账户，汇总级计划包，计划包和工作包中。在大型项目中，建立控制账户是将责任和权力下放到执行组织各个部分的主要方法。控制账户是一个单元格责任分配（RACI）矩阵，它是项目WBS和组织分解结构（OBS）的交集。控制账户被分配给控制账户经理（CAM）。大型项目需要更多精细的流程来控制基准修订，与分包商EVM系统更加彻底的整合，以及对采购物料的更精细管理。
In the United States, the primary standard for full-featured EVM systems is the ANSI/EIA-748A standard, published in May 1998 and reaffirmed in August 2002. The standard defines 32 criteria for full-featured EVM system compliance. As of the year 2007, a draft of ANSI/EIA-748B, a revision to the original is available from ANSI. Other countries have established similar standards.
在美国，全功能EVM系统的主要标准是1998年5月发布并于2002年8月重申的ANSI / EIA-748A标准。该标准定义了全功能EVM系统合规性的32个标准。截至2007年，ANSI / EIA-748B草案，ANSI原始版本的修订版本。其他国家也制定了类似的标准。
In addition to using BCWS and BCWP, prior to 1998 implementations often use the term actual cost of work performed (ACWP) instead of AC. Additional acronyms and formulas include:
除了使用BCWS和BCWP之外，1998年之前的实施经常使用术语实际工作成本（ACWP）而不是AC。其他首字母缩写词和公式包括：
- Budget at completion (BAC)
完成预算（BAC） - The total planned value (PV or BCWS) at the end of the project. If a project has a management reserve (MR), it is typically not included in the BAC, and respectively, in the performance measurement baseline.
项目结束时的总计划值（PV或BCWS）。如果项目具有管理储备（MR），则通常不包括在BAC中，并分别包含在绩效评估基准中。 - Cost variance (CV)
成本差异（CV） - CV greater than 0 is good (under budget).
大于0的CV是好的（低于预算）。 - Cost performance index (CPI)
成本绩效指数（CPI） 
- CPI greater than 1 is favourable (under budget):
CPI大于1是有利的（低于预算）： - < 1 means that the cost of completing the work is higher than planned (bad);
<1表示完成工作的成本高于计划的成本（差）; - = 1 means that the cost of completing the work is right on plan (good);
= 1意味着完成工作的成本在计划上是正确的（好）; - > 1 means that the cost of completing the work is less than planned (good or sometimes bad).
> 1意味着完成工作的成本低于计划（好或有时不好）。 - Having a CPI that is very high (in some cases, very high is only 1.2) may mean that the plan was too conservative, and thus a very high number may in fact not be good, as the CPI is being measured against a poor baseline. Management or the customer may be upset with the planners as an overly conservative baseline ties up available funds for other purposes, and the baseline is also used for manpower planning.
CPI非常高（在某些情况下非常高，仅为1.2）可能意味着该计划过于保守，因此很高的数字可能实际上并不好，因为CPI是针对较差的基线进行衡量的。管理层或客户可能会对规划人员感到不满，因为过于保守的基准线将可用资金用于其他目的，基准线也用于人力规划。
- Estimate at completion (EAC)
完成评估（EAC） - EAC is the manager's projection of total cost of the project at completion.
EAC是经理对完成项目总成本的预测。
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- This formula is based on the assumption, that the performance of the project (or rather a deviation of the actual performance from a baseline) to date gives a good indication of what a performance (or rather deviation of a performance from a baseline) will be in the future. In another words this formula is using statistics of the project to date to predict future results. Therefore it has to be used carefully, when the nature of the project in the future is likely to be different from the one to date (e.g. performance of the project compare to baseline at the design phase may not be a good indication of what it will be during a construction phase).
这个公式是基于这样的假设，即项目的绩效（或者实际绩效与基线的偏差）能够很好地表明绩效（或者说绩效与基准的偏差）将会是什么在将来。换句话说，这个公式是使用该项目的统计数据来预测未来的结果。因此，当项目未来的性质可能与迄今为止的性质不同时（例如，在设计阶段与项目基准相比，项目的性能可能并不能很好地表明它将会如何在施工阶段）。 - Estimate to complete (ETC)
估计完成（ETC） - ETC is the estimate to complete the remaining work of the project. ETC must be based on objective measures of the outstanding work remaining, typically based on the measures or estimates used to create the original planned value (PV) profile, including any adjustments to predict performance based on historical performance, actions being taken to improve performance, or acknowledgement of degraded performance.
ETC是完成项目剩余工作的估算。ETC必须基于剩余未完成工作的客观衡量标准，通常基于用于创建原始计划价值（PV）概况的措施或估算，包括根据历史绩效预测绩效的任何调整，为改进绩效而采取的行动，或确认性能下降。 - While algebraically, ETC = EAC-AC is correct, ETC should never be computed using either EAC or AC. In the following equation,
虽然代数，ETC = EAC-AC是正确的，ETC应该从不使用任何EAC或交流来计算。在下面的等式中，
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- ETC is the independent variable, EAC is the dependent variable, and AC is fixed based on expenditures to date. ETC should always be reported truthfully to reflect the project team estimate to complete the outstanding work. If ETC pushes EAC to exceed BAC, then project management skills are employed to either recommend performance improvements or scope change, but never force ETC to give the "correct" answer so that EAC=BAC. Managing project activities to keep the project within budget is a human factors activity, not a mathematical function.
ETC是自变量，EAC是因变量，AC是根据迄今的支出确定的。ETC应该如实报告以反映项目团队的估计，以完成杰出的工作。如果ETC推动EAC超过BAC，则采用项目管理技能来推荐性能改进或范围更改，但不要强迫ETC给出“正确”答案，以便EAC = BAC。管理项目活动以使项目保持在预算之内是一项人为因素活动，而不是数学功能。 - To-complete performance index (TCPI)
完整的性能指标（TCPI） - The TCPI provides a projection of the anticipated performance required to achieve either the BAC or the EAC. TCPI indicates the future required cost efficiency needed to achieve a target BAC (Budget At Complete) or EAC (Estimate At Complete). Any significant difference between CPI, the cost performance to date, and the TCPI, the cost performance needed to meet the BAC or the EAC, should be accounted for by management in their forecast of the final cost.
TCPI提供了实现BAC或EAC所需的预期性能的预测。TCPI指出实现目标BAC（预算完成）或EAC（预计完成）所需的未来所需成本效率。管理层在预测最终成本时应将CPI，迄今为止的成本绩效与TCPI（满足BAC或EAC所需的成本绩效）之间的任何显着差异考虑在内。 - For the TCPI based on BAC (describing the performance required to meet the original BAC budgeted total):
对于基于BAC的TCPI（描述达到原BAC预算总量所需的性能）：
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- or for the TCPI based on EAC (describing the performance required to meet a new, revised budget total EAC):
或基于EAC的TCPI（描述实现新的经修订的预算总EAC所需的性能）：
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- This implies, that if revised budget (EAC) is calculated using Earned Value methodology formula (BAC/CPI), then at the moment, when TCPI based on EAC is first time calculated, it will always be equal to CPI of a project at that moment. This happens because when EAC is calculated using formula BAC/CPI it is assumed, that cost performance of the remaining part of the project will be the same as the cost performance of the project to date.
这意味着，如果修订预算（EAC）是使用挣值法计算公式（BAC / CPI）计算的，那么在此时，当首次计算基于EAC的TCPI时，它总是等于该项目的CPI时刻。发生这种情况的原因是，当使用公式BAC / CPI计算EAC时，假设项目其余部分的成本绩效与项目迄今为止的成本绩效相同。 - Independent estimate at completion (IEAC)
完成时的独立估计（IEAC） - The IEAC is a metric to project total cost using the performance to date to project overall performance. This can be compared to the EAC, which is the manager's projection.
IEAC是衡量总成本的指标，它使用迄今为止的性能来预测总体性能。这可以与经理预测的EAC进行比较。
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Limitations
限制
Proponents of EVM note a number of issues with implementing it,[11][12] and further limitations may be inherent to the concept itself.
EVM的支持者注意到实施它的许多问题[11] [12]，而且这个概念本身可能存在进一步的局限性。
Because EVM requires quantification of a project plan, it is often perceived to be inapplicable to discovery-driven or Agile software development projects. For example, it may be impossible to plan certain research projects far in advance, because research itself uncovers some opportunities (research paths) and actively eliminates others. However, another school of thought holds that all work can be planned, even if in weekly timeboxes or other short increments.
由于EVM需要量化项目计划，因此通常认为它不适用于发现驱动或敏捷软件开发项目。例如，可能不可能事先规划某些研究项目，因为研究本身揭示了一些机会（研究路径）并主动消除了其他研究项目。然而，另一派思想认为，即使在每周的时间框或其他短暂的增量中，也可以计划所有的工作。
Traditional EVM is not intended for non-discrete (continuous) effort. In traditional EVM standards, non-discrete effort is called "level of effort" (LOE). If a project plan contains a significant portion of LOE, and the LOE is intermixed with discrete effort, EVM results will be contaminated.[13] This is another area of EVM research.
传统EVM不适用于非离散（连续）工作。在传统的EVM标准中，非离散的努力被称为“努力水平”（LOE）。如果一个项目计划包含很大一部分LOE，并且LOE与离散努力混合在一起，则EVM结果将受到污染。[13]这是EVM研究的另一个领域。
Traditional definitions of EVM typically assume that project accounting and project network schedule management are prerequisites to achieving any benefit from EVM. Many small projects don't satisfy either of these prerequisites, but they too can benefit from EVM, as described for simple implementations, above. Other projects can be planned with a project network, but do not have access to true and timely actual cost data. In practice, the collection of true and timely actual cost data can be the most difficult aspect of EVM. Such projects can benefit from EVM, as described for intermediate implementations, above, and Earned Schedule.
传统的EVM定义通常假设项目会计和项目网络进度管理是从EVM中获得收益的先决条件。许多小型项目不满足这些先决条件中的任何一个，但它们也可以从EVM中受益，如上面对于简单实现所述。其他项目可以通过项目网络进行规划，但无法获得真实且及时的实际成本数据。实际上，收集真实且及时的实际成本数据可能是EVM最困难的方面。这样的项目可以从EVM中受益，如上述中间实现所述，以及获得的计划。
As a means of overcoming objections to EVM's lack of connection to qualitative performance issues, the Naval Air Systems Command (NAVAIR) PEO(A) organization initiated a project in the late 1990s to integrate true technical achievement into EVM projections by utilizing risk profiles. These risk profiles anticipate opportunities that may be revealed and possibly be exploited as development and testing proceeds. The published research resulted in a Technical Performance Management (TPM) methodology and software application that is still used by many DoD agencies in informing EVM estimates with technical achievement.[14] The research was peer-reviewed and was the recipient of the Defense Acquisition University Acquisition Research Symposium 1997 Acker Award for excellence in the exchange of information in the field of acquisition research.
作为克服对EVM与定性绩效问题缺乏联系的反对意见的手段，海军航空系统司令部（NAVAIR）PEO（A）组织在20世纪90年代后期启动了一个项目，通过利用风险概况将真正的技术成果整合到EVM预测中。这些风险概况预测了可能会被揭示的机会，并可能在开发和测试收益时被利用。已公布的研究结果形成了技术性能管理（TPM）方法和软件应用程序，许多国防部门机构仍在使用该方法和软件应用程序来通知EVM估计的技术成果。[14] 这项研究经过同行评审，并因获得研究领域的信息交流卓越而获得1997年国防采办大学收购研究研讨会Acker奖。
There is the difficulty inherent for any periodic monitoring of synchronizing data timing: actual deliveries, actual invoicing, and the date the EVM analysis is done are all independent, so that some items have arrived but their invoicing has not and by the time analysis is delivered the data will likely be weeks behind events. This may limit EVM to a less tactical or less definitive role where use is combined with other forms to explain why or add recent news and manage future expectations.
定期监控同步数据定时存在固有的困难：实际交付，实际开票和EVM分析完成的日期都是独立的，因此有些项目已到达，但他们的发票尚未开始，并且分析时间已交付数据可能会比事件晚数周。这可能会将EVM限制在较少的战术性或较不确定的角色中，如果将其与其他形式结合使用来解释为什么或添加最新消息并管理未来预期。
There is a measurement limitation for how precisely EVM can be used, stemming from classic conflict between accuracy and precision, as the mathematics can calculate deceptively far beyond the precision of the measurements of data and the approximation that is the plan estimation. The limitation on estimation is commonly understood (such as the ninety-ninety rule in software) but is not visible in any margin of error. The limitations on measurement are largely a form of digitization error as EVM measurements ultimately can be no finer than by item, which may be the Work Breakdown Structure terminal element size, to the scale of reporting period, typically end summary of a month, and by the means of delivery measure. (The delivery measure may be actual deliveries, may include estimates of partial work done at the end of month subject to estimation limits, and typically does not include QC check or risk offsets.)
由于数学的计算结果远远超出数据测量的精度和计算估算的近似值，因此EVM的精确度和准确度之间存在经典冲突，因此存在测量限制。对估计的限制通常是可以理解的（例如软件中的九十九规则），但在任何误差范围内都不可见。测量的局限性主要是数字化误差的一种形式，因为EVM测量最终不会比按项目更细，这可能是工作分解结构终端元素大小，报告期的范围，通常是一个月的结束汇总，以及交付方式。（交付措施可能是实际交付，可能包括估计月底完成的部分工作，但需要接受估计限制，并且通常不包括质量控制检查或风险抵消。）
