CONTROLLING PROJECT COST, TIME, AND QUALITY
Project control begins with the identification of the owner objectives and ends when those objectives have been met. The owner, the designer and the construction professional together design, estimate and schedule the project to meet these objectives. This is the basis of the control system. On large or complicated projects, the control eflfort is a major undertaking with multiple organizations involved.
The purpose of project control is to guarantee that the project’s design, budget, and schedule are met by the project team. If any objective begins to slip, the control system will identify this deviation early so that the appropriate correction can be made.
Project control begins with a plan that identifies the objectives of the project and specific checkpoints throughout the project cycle. The plan is a roadmap that allows the project team to constantly monitor and make corrections as necessary. It consists of design documents for quality checks, an estimate that establishes budget requirements, and a schedule fbr project milestone dates.
Project control is an action-based process that encourages continual monitoring of operations. To be successful^ the actual work with its cost and duration must be completely and accurately documented. Comparisons should be made to project standards and variances noted. By creating such a feedback loop, adjustments can be made fbr upcoming activities. In addition, actual durations, costs, and important events should be recorded for use on future projects.
- PROJECT CONTROL OBJECTIVES
A system of control is essential fbr the successfill delivery of any construction project. To begin the process, managers first establish the standards that define success fbr the construction project. Cost, schedule, and quality are the basis of these standards and are configured so that they are measurable and can provide direction to the project. The project team will continually use these standards to check progress and provide direction. Just as transport aircraft, cargo ships, and truckers are tracked at specific checkpoints to monitor progress, construction projects must continually report
The standards used for control vary by project depending on the level of control necessary. Fast-paccd projects with many parties and contractual obligations must be more tightly monitored than a single contractor’s excavation project, for instance. Drawings and specifications define the standards fbr quality control..Drawings define the quantity of work required, locations, and widths and heights. Specifications provide performance standards that address alignment, compression strengths, finishes, and so on. The project estimate establishes the overall budget fbr the project and can be broken down to specify milestone costs fbr each component of work. The schedule defines when specific work items need to be accomplished as well as provides key milestone and delivery dates. Estimating data can be integrated with schedule information to provide additional project standards.
Standards serve as the goals fbr the project participants. They are targets and, if well thought out, can organize a very complicated project. Each project participant can be given a task with a corresponding budget and time frame in which to accomplish the job.
- Actual s
The second component of the project control system is measurement of actual progress. This includes accurate cost, schedule, and quality information about the project. Actual performance compared to planned performance provides the management team with feedback about how well the project is proceeding. Also, actual cost and schedule performance information can be stored fbr reference when estimating and scheduling future projects.
Measuring actual performance is a complicated process since the necessary information resides in many different places. An on-site review of daily reports, a walk-through by trained schedulers, submitted quantity reports, or video reports can provide information about the percent complete fbr the project. If properly cost-coded, worker time sheets and equipment logs can define how many hours were spent working on a particular task. These documents also define the labor and equipment costs that can be charged to a particular project. Purchase orders, delivery tickets, and receipts provide actual costs for material, equipment, and vendor purchases. Weather conditions and unforeseen circumstances can be picked up from daily reports. Such information provides the raw material for the project control reports necessary to monitor progress. These reports will then be properly processed, sorted, filtered, and delivered to the appropriate managers in a timely manner, illustrate a report showing actual performance compared to budgeted performance..
The feedback from the data can only be useful if put together in a combined form so that the correlation among cost, schedule, anticipated events, and unanticipated ones can be examined. The hours expended are greater than the hours budgeted fbr the work.
Once the project management team has this information, it then determines which reason or reasons explain the variance noted in the report. A check of past daily reports should verify the weather fbr the reporting period. A walk through the site with the superintendent and the estimator will give the team information about the approach being used, the actual site conditions, and the time and quantities assigned in the estimate. If the estimate, site conditions, and weather all appear to be normal, then worker performance should be examined. If a worker has little experience at a task, supervision is not adequate, work hours are too long, or the conditions of the job site are not conducive to productivity, the explanation fbr the variance probably resides in performance issues.
Key to the reporting process is that any inconsistency be identified quickly and the proper adjustment made in a timely manner. Good reports are accurate, show variances (differences) between budgeted amounts and actual amounts, forecast goals fbr future work periods, and suggest corrective actions. Timeliness is also important: if all the appropriate tasks have been accomplished but too late fbr any corrective action, the control effort has been wasted.
- BASIC CONTROL THEORY
The process of project control can best be illustrated as a control loop that repeats itself in a similar pattern.
The control process begins with the initial project plan, which includes budget, schedule, and quality along with other planning information such as staffing and administrative procedures. This plan is the result of the work of many different people and requires technical input and a commitment firom management. The estimate and the schedule arc the primary control tools described here, but the level of quality as defined by the design documents are also managed during construction.
- PREPARING A PROJECT FOR CONSTRUCTION
Preparing a project for construction means that the project must be broken down to a suitable level of detail so that it can be monitored and controlled. Establishing the scheduling activity as a common denominator often works because cost, time, and quality-control standards can be set up for each activity. Creating a baseline (also called a target or project forecast) is the first step in the control process. The baseline establishes the goals fbr the project and allows management to measure how well the project is proceeding and what the end result will be. The estimate serves as the cost baseline fbr a project, while the schedule serves as the time baseline.
- Cost Baseline
The estimate is the tool used to establish the costs on a project. These costs are later refined as a project proceeds. The conceptual estimate the first estimate performed establishes the initial cost for the project. As design proceeds, square foot and assemblies estimates tighten up the budget. Once the design is complete, bids are solicited, with the accepted bid price establishing the construction budget for the project. This budget is based upon a detailed estimate prepared by the contractor using a complete design and including many subcontractor and vendor quotes.
From the contractorj perspective, the accepted bid price, which becomes the contract price, is the cost baseline for the project and the target by which the success of the project will be measured. Material quantities, labor unit prices, and assumed productivity rates used in this estimate become the base-lines to measure the project success. From the designer’s and the owner’s perspective, the agreed-upon contract price is the culmination of a series of pricing exercises that have been prepared since the first conceptual estimate. If the scope of the project has been well managed and the estimates done well, then the bids received should be close to the prior estimates. The quality of the contract documents, the bidding environment, and the location and type of project are all factors that affect the prices received.
Throughout the dcsign/build process, the application of Pareto’s Law plays an important part in the control of project costs. Vilfredo Pareto (1848^1923), an Italian economist, believed that 80 percent of the outcome of any project is determined by 20 percent of its included elements. Thus, any project control system needs to identify the major cost elements of the project early and develop a system of controls to monitor and manage them. Projects are broken down through the CSI format, a work breakdown structure (WBS), and bid or work packages. In some cases these may or may not be the same. Project managers focus on the elements that will have the greatest impact on the final project cost and/or the element with the greatest risk of escalation.
The estimate is clearly the baseline for the control of project costs. As the project moves to the construction stage, the estimate becomes extremely detailed, with numerous items to control and monitor. The detailed estimate provides specific direct cost targets such as material quantities, labor rates, equipment rates, and hours as well as indirect cost elements such as field overhead, contingency, and home office overhead. At this stage the application of Pareto’s Law becomes important. By using detailed and summary reports, project managers fbcus on the elements in need of tight control and only look at less critical elements at a summary level.
- Time Baseline
Through the schedule the project team manages the time and related resources required to complete the project. When the schedule is combined with the estimate, the cash flow can be projected. To do this accurately, the schedule must be managed and continually updated to reflect the work that is occurring in the field. As with cost control, the schedule can be used either at a summary level or at the more detailed level, depending on the level of control required. Using bid packages, WBS, and the CSI can establish the necessary levels of control. Detailed control can be managed through network schedules, whereas summary control can be handled through bar charts or timetables.
Most projects are developed in full detail using a network-based CPM schedule with summary reports generated as necessary fbr reporting purposes. For example, on large projects detailed network schedules are developed for each of the major systems, which is necessary to coordinate and control the system work. However, when the project is examined in its entirety, the system work is shown only as a single bar.
- COST AND SCHEDULE PERFORMANCE MODELS
Cash, 1 汰c people and equipment, is a resource that must be tightly controlled on a project. It is the rare owner that begins a project with cash equivalent to the project budget sitting in the bank. The owner needs to know, with accuracy, how much cash must be available each month of the project to pay the contractors invoices. Like the owner, the contractor must be able to predict his or her cash needs for a project. Contractors receive income from the owner in the form of paid invoices. That cash is then paid out to in-house labor, subcontractors, and material and equipment suppliers. To stay in business, the contractor must diligently manage these cash flows.
Managing cash flow is made difficult by the fact that payments are made in different increments depending on the type of activity. Subcontractors generally invoice the general contractors at the end of each month fbr the work completed. The general contractor typically pays the subcontractor after the owner has paid the general contractors invoice. A general contractor pays his or her labor at the end of each week. Materials are generally provided to the contractor on credit, with the contractor paying the supplier in full at the end of the month. To properly project cash flow, each activity must be tracked in the manner in which the payment will be made.
The cost of each activity must first be identified from the estimate and assigned to the corresponding activity on the schedule. By calculating the cost per day to irind each activity (activity cost/activity duration), also called the cost slope, the project manager can calculate the total cost per day to run the project. These costs can be added up weekly or monthly. The figure illustrates a cost-loaded schedule and is the basis fbr projecting both income and costs.
- Income Projection
A schedule of values curve is the cost-loaded schedule that projects the value of work that is planned to be invoiced at the end of each payment period. This is prepared in advance of construction and submitted to the owner or owner’s agent for approval. The income that the contractor receives is the amount of the invoice less owner retain age. Retain age is money held back by the owner until the contractor satisfactorily completes the contract. Retain age of 5 to 10 percent of the amount invoiced is normal. The income curve is a step curve, reflecting the fact that the contractor submits an invoice at the end of each payment period equal to the schedule of values curve and will receive a payment three weeks later equal to that value less retain age. No income is received until the next invoice is paid one payment period later. All retain age is paid to the contractor at the end of the project. The final point on the schedule of values curve equals the income curve, which equals the contract amount.
The projected payment period totals are commonly negotiated between the contractor and the owner. It is in the contractor’s best interest to shift as much value as possible to the front of the job, overvaluing early activities while undervaluing later items. This ploy is commonly called °front-end loading?” Within reason, this is an accepted practice since in the early part of a project contractors often are faced with hidden costs not easily attached to specific work activities. This also helps offset owner retain age, which can severely affect a contractor’s cash flow.
When assigning a cost to an individual activity, the contractor must be sure that the amount attached reflects his or her complete costs, including both direct and indirect costs and profit. Subcontractor costs must be marked up, and material and labor costs must also include appropriate markups. The costs assigned to each activity are what will be eventually billed to the owner; therefore, all costs and profit must be identified.
- Payment Projection
Before construction the contractor should prepare a payment projection (also called a cash requirements curve), which projects the cash payables expected from the contractor to run the project. This curve is prepared
similarly to the income curve except that now the contractor is forecasting the cash that is leaving the company to pay for labor, materials, subcontracts, and other commitments. Another difference is that the costs assigned to each activity arc direct costs and do not include general contractor overhead or profit, which are not directly paid out. At the end of the project, the final point on the cash requirements curve indicates the total amount of money that the contractor has spend for labor, materials. Equipment, and subcontracts, just as the income curve reflect the total amount of money paid to the contractor by the owner.
Cash requirement and income projections should be done for all company projects since most companies have projects running at different stages of completion. Projects requiring an influx of cash can be helped by other projects that are nearing completion and generating positive cash flow.
- CONTROL IN ACTION
A project begins with a work plan that includes a budget, a schedule, and an engineered approach designed to complete the project most effectively. Preparing a work plan involves the many project participants, whose goal is to most efficiently use the company’s resources. The estimate and the schedule form the basis of an analysis of the project.
Projects begin with this plan, but the reality of construction is that events occur that force the plan to be altered. An owner adds or deletes work, forcing a change in the projects scope; bad weather interrupts the project; a labor strike occurs; or productivity in the field is less than planned. To manage these events, the project team must establish a system to capture the actual, event of the project, analyze them, and make appropriate adjustments so that the projects budget, schedule, and level of quality are adequately maintained.
- Cost Engineering
For the project team to effectively manage and control the construction process, data used to compare against the baseline system are first generated in the field. Developing an effective method of gathering and analyzing these data is key to maintaining control over the construction process.
People sometimes liken cost engineering to cost accounting, but the two disciplines should not be confused. Both arc concerned with costs, but the accountant focuses on historical costs fbr tax purposes, bill paying, and invoicing of clients. The cost engineer, on the other hand, is concerned with forecasting and trending, using project information to measure how well a project is doing and what the outcome will be. The two disciplines must work together. The accountant needs project information to properly invoice customers and to pay bills. The project manager uses accounting information for estimating and budgeting purposes.
- Progress Evaluation and Control
The estimate and schedule prepared before the project begins establish the baseline fbr the construction project. Once the project begins, actual progress is periodically determined so that any necessary adjustments can be made quickly. Through the cost coding system, actual cost information about the project is also collected. Actual progress when combined with actual cost to date allows the productivity on the project to be measured. Productivity information, cost to date, and schedule progress help management properly control a project.
The method used to measure work progress depends on the type of work. Following are several different approaches.
- Incremental Milestone
When an activity involves an operation that will be accomplished in a specific, known sequence, the approximate level of effort necessary to accomplish each milestone (usually based on the number of hours required) is measured.
- Cost Ratio
This method is used fbr tasks that occur over a long period of time and are continuous throughout. Project management and quality assurance programs are examples. These services are budgeted by dollars or work hours.
- Other Methods
The previous methods are the most common, but other methods of measuring progress are sometimes used when activities are composed of specific work elements that are of very different cost or work effort. Here the work may need to be prorated to account for the disparity. In some cases, (creative work is an example) it is very difficult to determine how long an
activity will take and how much has been done. In this case the physical start of the activity can be assigned 50 percent complete and the completion 100 percent. In the end, the subjective opinion of the supervisor may be the only option, but this should only be resorted to when other more objective methods are impossible.
Determining the percent complete of an activity is an important step in the control process. Once the progress of an activity is determined, it is possible to compare the present status of a project with the baseline. This comparison is the best way to determine how the project is proceeding and if any remedial actions need to be taken.
- Cost and Schedule Performance
The evaluation of actual performance to planned performance is a critical and recurring step in the control process. Actual is compared to planed on an activity-by-activity basis. The level of detail that can be evaluated depends on the level of detail established within the cost-coding system. The frequency of this evaluation depends on the type of project and the level of control required. The greater the level of detail established and the more frequent the reviews, the greater the cost of the control system.
Project control is a continuous cycle in which project managers identify a goal, measure results, analyze, make adjustments, and report results. It is an action-based process with a feedback loop that can cycle as often as necessary, depending on the nature of the project. The estimate and the schedule establish the cost and timing goals. As the project proceeds, the actual results are compared to the target dates and costs established by the estimate and schedule. Significant deviations from the plan should be analyzed so that corrections can be made either in the ongoing project or in the company’s data base so that future estimates and schedules will not repeat mistakes, Project control should be viewed as a learning process in which team members exchange information, make adjustments, and record results.
In establishing the initial project plan, the team integrates the estimate and the schedule to arrived at the most optimum schedule and budget for the project. Estimates and schedules are usually prepared independently; but as the final preparations are made for the project, every effort should be made to integrate the two. When projects arc shortened, indirect costs arc saved while direct costs go up. The optimum duration is the duration at which the project can be constructed fbr the least cost. This is found by analyzing the projects critical path and crashing critical activities as long as the direct cost of shortening the project is less than the indirect cost of the project.
Field performance is periodically measured with the actual results comja pared to the set standards. The level of detail is determined by the cost-coding system adopted for the project. As the level of detail increases, the cost of managing the control process increases.
Performance is calculated by computing cost and schedule variances and performance indices. Productivity performance is also measured. Managers use these calculations to analyze the project’s performance and make changes if necessary Actual performance data and any other information about the project need to be documented and stored. Management decisions need to be communicated promptly to all key project participants. A timely response from management gives feedback to the field and provides ample opportunity fbr the field to implement any recommendations. The last control responsibility is fbr management to continually report on the progress of the project. Reports should be timely, should indicate key variances between budgets and actual as well as project trends, and should forecast the projects completion cost and date.
控制工程贯穿于工程活动的始终。建设方、设计方与施工方的专业技术人员通力 合作，致力于达到这个目标。这是控制系统的最基本理论。在大型或复杂工程中，控 制工作关系到工程的命运。
项目的目的是控制，以确保项目的设计，预算和时间吻合施工进度要求。如果任 何一个环节出现漏洞，控制系统将弥补这些漏洞以即使纠正偏差保证工程活动顺利进 行。
控制工程，依据一个计划确定项目的目标和具体的检查整个项目周期。该计划是 一个目标以此让施工单位不断地监测并作采取必要的纠正措施。它包括设计文件质量 进行抽查，估计确立预算要求.和时间表项目里程碑的口期。
控制工程，是一个行动的过程，它不断进行检查纠偏。要取得成功，必须完整地， 准确地记载在实际工作中的费用和时间，通过建立这种反馈回路调整，可为即将进 行的活动比较应向项目和标准的差异。此外，实际时间，成本和重大事件应记录，供 日后的发展项目借鉴。
一个完整的控制体系对于任何一个成功验收提交的工程来说都是十分必要的。为 开始这项进程，管理者首先确立标准，定界成功的建筑项目。成本，进度和质量是最 基本的衡量标准与数据，以确保控制体系可以为整个工程进度提供方向性指引。项目 组将不断利用这些标准来检查进展情况，并提供指导.就像飞机运输，货运船,在特定 的检查，监测中纠正错误，建设项目必须同样地不断作出报告。
用于工程的控制标准取决于该工程适用控制措施的必要性程度。工期紧节奏快的 项目由许多施工单位与管理者参与，这时就必须投入比一个承包商更多的经历严密监 督与控制。比如开挖工程，图纸和技术指标的界定标准和质量控制。图纸决定工程 所需要的质量标准、地点及尺寸规模。规格提供业绩标准，地址线，压缩强度，表而 装饰，等等。工程概算确定的总预算项目，每一部分的工作可细分为具体单位工程费 用。时间表确定具体必须要完成的工作项目，以及提供关键的里程碑和交付日期。估 算数据可以结合附表资料，以提供额外的项目标准。
标准作为项目参与者的H标，这些目标如果经过深思熟虑之后，可以组织一个 非常复杂的系统工程.每个项H参与者可以得到一个任务与相应的预算和时间框架 内要完成的作业安排.
项目控制系统的第二组成部分是衡量实际工程进度。这包括有关项目准确的成 本，进度和质量。抓好项目跟进实际绩效与计划绩效提供管理团队反馈关系到项目是 否运作良好。另外，实际成本和日程业绩信息可以储存以备参考估算和调度未来项目o
测量实际进度，是–个殳杂的过程。因为在许多不同的地方，必要的信息因工程 而异。对每日现场审查报道，过程训练调度，数量提交报告或录像报道都可提供工程 完成情况百分比的资料。如果费用被分配的合理，从工作时间表和设备利用表中我们 还可以分析得出在某–个具体任务上我们需要消耗多少工时。这些文件也确定了劳动 力和设备的费用，可以计入某一特定项目。采购订单、交货票据、并提供收据实际费 用材料，设备和供应商购货都是必要的。天气和突发情况可以从每日报告中摘录出来。 这些报告将得到妥善的处理，分拣，过滤，并交付给适当的管理者作出及时的分析处 理。这说明了一份报告，显示实际业绩与预算的比较情况。
很显然，从反馈的数据只能表明是有益的，如果一个联合的形式放在一起使成本、 进度、预期事件关联在…起，出乎意料的可以研究出结果。时间支出的效益远远大 于项目进程中一-个小时的支出。
一旦项目管理团队有这方而的资料，就可以决定使用何种理由解释差异的报告指 出。一个关于过去天气的报告应符合过去每日的天气情况，布置现场预警估计会给 团队提供有关使用办法外，还对现场的实际情况，花费的时间和分配数量的估计.如 果估计，场地条件，天气一切看来都是正常的，那么工人的表现应予以审查.如果一 个工人的小经验，在一个任务时监督不够，工作时间过长或条件的不成熟是不利于生 产力，可能在于性能问题解释的差异。关键过程中的报告，就是对任何不一致应迅 速查明并适当作出调整，及时改变方式。好的报告应该是准确的，为今后的工作时 段表明差额（分歧）之间的预算金额与实际金额，预测目标并对其提出纠正行动。及 时性也很重要：如果一切合适的任务已经完成，来不及采取任何补救行动时为时已 晚，此时控制的努力已经白费。
控制过程与整个工程的进度计划相关，它包括预算、时间表、需要符合最初的计 划信息，如人事及行政程序。这个计划是很多不同的人，通过技术的投入和承诺管理 的成果。这里形容估计及主要控制工具但通过设计文件确定的工程质景水平也可在施 工过程中进行管理。
准备工程施工意味着项目必须被分解为一个合适的详细程度，以备监测和控制。 建立调度活动的一个共同点往往作为工程成本、时间和质量的控制标准，建立基准 （乂称目标或预测项目）是控制过程的第一步。基线确定了对项目的目标，方便管理 者衡量项目进程及预测项目的最终结果。这些最基本的功能作为工程成本控制的基 准，就像进度表作为时间控制的基准。
成本基线的估计是用来确定一个项目的成本，这些费用在后期用来衡量项目的进 程，作为设计收益平方和集会估计收紧预算。一旦设计完成后，项目的管理者就投 标的要求，接纳标价建立建设项目预算。这份预算案是根据一个详细的估计承包商 编写使用一个完整的设计，其中包括许多分包价和卖方报价。
从承包方角度来说，公认的成交价，使之成为合同价格。而旦是成本基准计划和 目标并假定生产率采用这一估计将成为衡量项目的成功与否的标准。从设计师与业主 的角度来看，材料数量、单位劳动力价格和商定的合同价格是经过一系列的沟通交流 和反夏琢磨的。合同文件的质量、招标环境的定位、项目类型等因素都影响价格。如 果项目的范围己被管理得井井有条而旦估计做得好，随后收到的标书应接近事先估 计。
通过设计/建造过程中，帕累托定律应用起着重要的作用。在控制工程成本，维 尔弗雷多帕累托（1848-1923 ）意大利经济学家,大多数相信80%以上的结果，任 何一个项目都是山20 %的内容列入。因此，任何工程控制系统都需要确定的主要成 本要素的项目并及早制订一项制度以控制监测和管理他们。进行项目细分，在某些情 况下可能不一样。通过倡议的形式，工作分解结构（WBS ）而出价或工作分包。
项目经理集中要素，对最终的工程造价和/或元素将有极大的影响。财务估计是 为控制工程成本成本的基线。因为工程将进入施工阶段，估计变得非常详细。有许 多项目的控制和监督。详细估算提供具体直接成本指标，如材料的数量、劳动率、 装备率和时间以及间接成本要素等领域的开销，应急和家庭办公室开销。现阶段的应 用帕累托定律就变得极为重要。用详细的总结报告，项目经理集中的元素需要严格 控制，只有看不太关键要素在其综述水平。
当结合估计，现金流可预期。通过项目管理团队的时间和相关资源才能完成这项 工程。这样做比较准确，其必须加以管理并不断更新以反映工作，与成本控制可用于 在–个简易-级或更详细的程度,似乎程度的控制要求。并倡议可以建立详细的控制。 可管理的必要的控制水平通过网络时刻表而简易控制。
大多数项目都制定详细使用网络化被动简要报告生成所需要的报告用途。例如在 大型工程项目的详细时刻表网络发展的各个主要系统，这是必要的协调和控制系统 的工作。但是当这个项目研究的全部内容，该系统的工作只表现为-个单一的项目。
现金、人、设备，都是一种资源，也是必须严格控制的…种资源。从项目与现 金等值的项目预算坐在池边。这从严格意义上需要业主了解并掌握准确需要多少现 金，多少用于每月的工程承包商付出的发栗。如业主，承包商必须能够预测他或她 的项目所需要的现金，承包商以支付票据的形式获得收入。这些现金乂用于雇佣劳动 力，分包商，材料采购及设备租赁。在商业活动中，承包商必须坚持不懈地控制这些 现金流量。
山于支付工程款时会因项目实际情况不同而产生各种支付方式，控制现金流量几 乎是很困难的。分包商大体上都会在月成的时候向总承包商开其发票以便于工程进 展，总承包商却总是在业主给他支付工程款之后支付分包商工程款。总承包商在每个 周末支付为他的工人支付报酬。承包商以信用卡支付的方式收到材料款，并用以支付 足够使用到月底的材料数量。为适当的控制现金流H，每种行为都需要以工程款被支 付的方式来进行讪录。
目经理可以控制何天的总成本以确保整个项目的运作。这些费用可以在每周或何月被 加总核算。这些数据说明了一个资金利用的进度，是控制项目收入和支出的重要衡量 尺度。
一个价值曲线的进度表就是一个成本装货时间进度表，它强调了被计划在每个支 付期末进行的工作的价值。它在工程建设之前被预先准备并交给所有者或所有者的代 理人审批。承包商得到的收入数量扣除了一定年限的滞留金。滞留金年限是指业主保 留-部分工程款直至承包商完全并令人满意的完成整个合同。通常情况下滞留金占工 程价款的5号到收入曲线是一个阶梯型的曲线，它反映了一个事实即承包商在 每个支付期末提交一 •个与进度价值曲线相应的发票并在三周后收到扣除滞留金后同 等价值的款项。所有的滞留金在工程结束的时候都会被支付给承包方。价值曲线上的 最后一点与收入曲线相吻合，也与合同约定相吻合。
工程付款期总数通常是承包商和业主之间需要协商解决的问题。承包商乐此不疲 地忙于在工程前期获取尽可能多的利润，尽可能提高前提工作的价格，降低后期工作 的价格。这种方法一般被称为“不平衡报价法”。这是-个公认的惯例，因为在工程 的早期，承包商往往而临着隐性成本无法附加到具体工程活动中的困扰，不平衡报价 法同时也有利于抵消工程款滞留期限，从而保持一-定的现金流量。
当指定–个具体工程的成本时，承包商必须确定这部分成本可以反映出他的全部 成本，包括直接或非直接的支出及收益。分包商成本必须被加上一定利润比例，材料 和劳动力成本也必须经过加价。每项具体进度的花费都要完整地呈报给业主，因此所 有的花费和收益都必须明确具体。
在工程开始建设之前，承包筒必须准备一个付款投影（又称现金需求曲线），这 条曲线反映了承包商运行整个项目需要的资金。这条曲线与收入曲线类似，除了在这 里承包商要预测需要留置以便公司支付给雇仰工人、材料购买分包及其他事务的资 金。另一点不同就是成本分配给每一个活动的是直接费用，不包括总承包费用或利润, 因为这些不是直接支付的。在工程结束时，现金需求仙线上的最后一点显示出了承包 商投入在劳动力、材料、机械以及分包中的总资金，就像收入曲线反映发包商支付给 承包商的总金额。
所有的工程活动都需要现金需求和收入投影，因为大多数的公司都会同时运营在 不同完工阶段的儿个不同的项目。需要大量:现金的项目可以从其他接近完工或已产生 正现金流量的项目中借取资金。
一个项目由一个工作计划开始，它包括一个预算，一个时间表和一个设计好的完 成项目最有效的方法。制定一个工作计划涉及到许多的项目参与者，他们的共同目标 就是最有效地利用市场资源。这些判断和安排组成了一个项目分析的基础。
项目由这项计划开始，但事实上项目进行过程中可能会有较大的事情发生迫使计 划必须改变。业主增加或减少工作，在工程范围而内强制进行变更；恶劣天气致使施 工中断；发生劳动罢工;或实际劳动生产力低于预期，这些都是可能发生的情况。为 处理这些问题，项目组必须建立一个系统去掌握这些实际情况，对工程影响较大的事 情，分析它们，并做出适当的决策，这样才能使工程的预算、进度和施工质量得到充 分保证。
为使项目团队有效地管理和控制建设项目进程，该领域中产生了运用数据去比对 基线的系统。发展-个有效的收集和分析数据的方法是在整个建设过程中保持控制权 的关键。
人们有时将成本工程比喻成成本会计，但两者不应该被混淆。两者都关系到成本, 但会计以税收为目的因此关注历史成本，草案夏发费和客户需要。另一方而，造价工 程师关系到预测和趋势，他运用工程信息来衡量项目的运行程度以及支出会是如何。 这两个学科必须共同协作。会计师需要的是项目信息以便妥善为顾客开具发票并付 账。项目经理则利用会计信息达到估算和预算的目的。
工程开工前的估算和行程准备为建设项目设立了一条基准线。一旦项目开工，必 须要求阶段性的实际进程，因此可以在很短的时间内做出必要的决定。通过成本编码 系统，也可以收集实际的成本信息。当实际的进程被整合到实际的同期成本时，工程 进程就可以被整合。工程信从，每期成本以及进度都帮助管理者适当地控制工程。
先前的方法是最常用的，但其他衡量进度的方法有时在其具体的工作成本或付出 的努力不同时使用的。在这里这项工作可能需要以比例来衡量。在-些情况下（创造 性工作，是其中一个例子），很难决定一项工作需要耗费多长时间以及多少费用。在 这种情况下，行为上的开始可能已经表示着任务指派了 50%,完成了 100%。到最后， 主观意见可能是唯一的选择。但这只能寄希望于其他方法都是不可行的。
决定一项活动的完成程度是控制进程中的一个重要步骤，一旦一个活动的进程被 决定了，就可以用来与基准线比较以对比项目当下进度。这种比较是衡量项目进程及 确定采取任何补救措施的最佳办法。
评价实际绩效与计划绩效是控制进程中一个重要和经常性的步骤。实际进程被用 来单对单地与项目进行比较。可以被衡量的细节水平取决于建立详细的成本编码系 统。这种价值衡量的频率取决于项目类型和控制的需要程度。细节水平越高衡量的越 频繁，控制系统的成本越高。
项目管理是一个持续不断的循环，其中项目经理确定一个目标，对测量结果进行 分析，作出调整并报告结果。这是一个项目性质的行动过程与反馈过程，往往取决于 项目需要。估计与时间表，建立成本利时间目标。随着项目的进程，以实际结果比对 预定日期和费用确定的估算和时间表。无论是在正在进行的项目或是还存在在该公司 的资料库，严重偏离计划的应进行具体分析以便更正，以免未来的估计和时刻表重蹈 复辙。控制工程应被看作是一个学习过程中，成员们互相交流信息，做出调整，并记 录结果.
在最初制定项目计划时，团队往往希望实现最优化的时间表和项目估算。预算利 时间表往往都是在没有依据的情况下被制定了出来，但随着最终计划的制定，应全力保证两者的结合。当项H工期缩短时，间接成本得到减少但直接成本又有所上升。最 佳时间是项目可以用最低成本被建成的时间。这建立在分析项目的关键路径和关键活 动上，只要直接成本的减少小于间接成本，项目都是可行的。
业绩以成本计算、进度曲线及差额为衡量的性能指标。生产力的表现也是一种衡 量方法。管理者使用这些计算分析项II的业绩和作出必要的改变，必要的实际性能数 据和其他任何工程信息也如此。管理决策须及时传达到各重点工程的参与者处.管理 者做出的及时的反应为项目提供支持，也为项目提供了执行任何建议的机会。控制的 最后-•项职能是方便管理者不间断地通知项目进程。报告应该是按时的，应说明关键 的差额预算和实际以及项目的发展趋势，要预测项目完工成本和日期0