Cost Management – Cost Control and Value Management

Preparing a good cost estimate is one skill. Keeping a project within that budget once work starts on site is quite another, and that is the job of construction cost control. The construction phase is where commercial discipline is truly tested. Scope creep accumulates quietly. Programme pressure drives costly decisions. And the gap between the cost plan and the likely outturn can widen week by week if nobody is actively managing it.

Cost control and value management are the disciplines that bridge the estimate and the final account. Done well, they give the project team a clear view of the financial position at all times. They also provide the information needed to intervene before problems become crises.

Post 4 of the Built Environment Series | For Quantity Surveyors, Project Managers, Construction Professionals & Students

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Cost Control vs. Cost Management

The two terms are often used interchangeably, but there is a useful distinction. Cost management is the broader discipline. It covers estimating, cost planning, procurement and final account settlement across the whole project lifecycle. Cost control is narrower. It is the real-time process of monitoring expenditure against budget during construction, identifying variances and taking corrective action.

Cost control without good cost management upstream is like navigating without a map. You can track where you are, but you have no reliable sense of where you should be. Equally, a well-prepared cost plan that is never updated during construction is a historical document. It is not a management tool.

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The Cost Plan: Setting the Baseline

Construction cost control can only be as good as the baseline it measures against. In the UK, that baseline is built up through the design stages using NRM 1, the RICS New Rules of Measurement for order of cost estimating and cost planning of building works.

NRM 1 links each stage of cost advice to the RIBA Plan of Work.

NRM 1 also sets a standard structure for the total budget. It separates the building works estimate from main contractor’s preliminaries and overheads and profit. It then adds project and design team fees, other development costs, risk allowances and inflation. That structure matters during construction. When the tender is accepted, the contract sum replaces the works estimate, but the other budget lines remain. Risk allowances become the contingency that the cost report tracks month by month.

A cost plan that has been properly structured and recorded is far easier to control against. Each element of the cost report can be traced back to a line in the approved budget. Any movement can then be explained in terms the client recognises.

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The Cost Report

The primary instrument of construction cost control is the cost report. It is a periodic document, usually monthly and aligned with the interim valuation cycle, that presents the current financial position of the project. It is the QS’s most important deliverable during the construction phase.

A well-structured cost report includes the following key components.

The Contract Sum

This is the starting point. It is the value of the construction contract as let, normally the corrected tender sum following tender analysis. It represents the agreed price for the original scope of work. Every subsequent change is measured against it.

Variations to Date

This is a summary of all variations instructed to date, grouped by status.

• Agreed. Fully valued and signed off with the contractor.
• Assessed. Valued by the QS but not yet agreed with the contractor.
• Anticipated. Instructed or expected, but not yet valued.

The variation log sits behind this summary and provides the detail.

It is important to distinguish clearly between agreed and unagreed variations. An assessed variation that the contractor disputes is not the same as one that has been formally agreed. Treating the two as equivalent can create a falsely optimistic picture of the project’s financial position.

Anticipated Final Account (AFA)

The AFA is the QS’s current best estimate of what the contract will cost at completion. It is sometimes called the forecast final cost or anticipated final cost. It includes the contract sum, all variations to date whether agreed or not, and the QS’s assessment of further costs that are expected but not yet instructed.

That last category requires professional judgement. The QS must look ahead and identify scope that is implicit in the current design or programme but has not yet been formally instructed.

The AFA is the single most important number in the cost report. It is the figure against which the budget is measured, and the one the client will scrutinise most closely. Consider a simple example for an £18.5M contract at month 9.

Only £420,000 of the £915,000 in variations has actually been agreed. The remaining £495,000 is the QS’s assessment. If the contractor’s view of the assessed items is higher, the overrun grows. A good cost report says so plainly.

Budget Comparison and Variance

The AFA is compared against the approved project budget, or the relevant part of it such as the construction budget. The variance is reported clearly, whether positive or negative, with an explanation of what is driving it. A well-written cost report does not simply state the variance. It explains it in terms the client can act on.

Risk and Contingency Status

The cost report should show the current status of the risk and contingency allowance. That means how much was included in the budget, how much has been consumed by identified risks, and how much remains. As the project progresses, risks either crystallise or are avoided. The contingency balance should reduce in a controlled way. It should not evaporate.

Cash Flow Forecast

Some clients have funding constraints or treasury reporting requirements. For them, the cost report should include a cash flow forecast showing the expected pattern of expenditure through to completion. This allows the client to manage drawdowns, funding facilities and financial reporting obligations. The free ProQS construction cash flow calculator produces an S-curve forecast with retention and payment timing from the contract sum, which makes a useful starting point.

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The Variation Log: The Engine of Cost Control

The variation log is the detailed record behind the cost report. It lists every change to the contract, whether instructed, anticipated or under consideration. Under JCT, these are architect’s or contract administrator’s instructions. Under NEC, they are compensation events. Each entry carries a current valuation status and financial assessment.

A well-maintained variation log has four characteristics.

It is exhaustive. Every change is captured, however small. The temptation to ignore minor variations is one of the most common causes of final account disputes. “It’s only a few hundred pounds, we’ll deal with it later” is how problems start. Small variations accumulate.

It is current. The log is updated as instructions are issued, not compiled retrospectively. A variation log that is six weeks out of date is not a cost control tool. It is a liability.

It distinguishes clearly between agreed and unagreed values. The financial exposure represented by unagreed variations is a risk to the project. It should be flagged and managed, not buried in a single aggregated total.

It tracks programme impact as well as cost. Variations do not only cost money. They take time. The log should note any programme implications so that extension of time entitlements can be tracked alongside the financial position.

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Earned Value Management

Earned Value Management, or EVM, is a more sophisticated approach to cost control. It integrates cost and programme data to give a single picture of project performance. It is widely used on large infrastructure and defence projects, and is increasingly applied to complex building schemes.

EVM is built on three core metrics.

Planned Value (PV), also called Budgeted Cost of Work Scheduled (BCWS). This is the value of work that should have been completed by a given date, according to the baseline programme and budget. It answers the question “what did we plan to have done by now?”

Earned Value (EV), also called Budgeted Cost of Work Performed (BCWP). This is the value of work actually completed, expressed at the original budget rates. It answers the question “what have we actually achieved, valued at the planned rate?”

Actual Cost (AC), also called Actual Cost of Work Performed (ACWP). This is what has actually been spent to achieve the earned value. It answers the question “what did the completed work actually cost?”

From these three metrics, a set of performance indicators can be derived.

• Schedule Variance (SV) = EV − PV. A negative SV means the project is behind programme. A positive SV means it is ahead.
• Cost Variance (CV) = EV − AC. A negative CV means the work completed has cost more than budgeted. A positive CV means it has cost less.
• Schedule Performance Index (SPI) = EV ÷ PV. An SPI below 1.0 indicates the project is behind schedule.
• Cost Performance Index (CPI) = EV ÷ AC. A CPI below 1.0 indicates the project is overspending relative to the value of work completed.

The power of EVM lies in its ability to forecast. The budget at completion (BAC) is the total approved budget. Dividing it by the current CPI gives an Estimate at Completion (EAC). This is a forecast of the final cost grounded in actual performance rather than optimistic assumptions.

Worked example

Consider a £20M project with a 20-month programme. At the end of month 10, the figures are as follows.

The project is 10% behind programme and spending around 6% more than budgeted for the work it completes. If that performance continues, the final cost will be about £21.2M, which is £1.2M over budget.

A more optimistic forecast assumes the remaining work will be delivered at budget rates. That gives an EAC of AC plus the remaining budget, which is £8.6M plus £11.9M, or £20.5M. The gap between £20.5M and £21.2M is the range the QS should discuss with the client. The question is whether the overspend so far was a one-off or reflects how the rest of the project will perform.

EVM requires detailed programme data and rigorous cost tracking to work properly. It is not appropriate for every project. On large, complex schemes, however, it gives a level of financial visibility that traditional cost reporting cannot match.

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Value Management and Value Engineering

Cost control is fundamentally defensive. It aims to keep the project within the approved budget. Value management is more proactive. It aims to maximise the value the project delivers relative to the money spent.

The two terms below are sometimes confused.

Value Management (VM) is a structured, facilitated process applied in the early stages of a project. It clarifies objectives, challenges assumptions and identifies the most cost-effective way to achieve the client’s goals. It is a strategic discipline, typically led by a specialist facilitator. It is most powerful at RIBA Stage 1 or 2, before significant design fees have been committed.

Value Engineering (VE) is a more specific, technical process. It focuses on reducing cost without reducing function. It involves a systematic review of each element or component of the design. For each one, the team asks whether it could be done differently, at lower cost, without compromising the performance or quality required. VE can be applied at any stage. It is most effective during detailed design, once the scheme is resolved enough for meaningful technical alternatives to be assessed.

It is important to be clear about what VE is not. Value engineering is not simply cutting scope, lowering the specification or omitting items the client wanted. That is cost reduction, and it should be presented and agreed as such. True VE identifies genuinely equivalent alternatives that deliver the same functional outcome at lower cost. One example is replacing a proprietary curtain walling system with an alternative that meets the same performance specification at a lower unit cost.

The VE Workshop

A structured VE workshop brings together the design team, the QS, the contractor if appointed, and key client stakeholders. The group reviews the cost plan element by element. For each element, the team asks four questions.

• What does this element do?
• What must it do, as a minimum?
• What alternatives exist?
• What are the cost, programme and risk implications of each alternative?

A well-run VE workshop on a major project can identify savings of 5% to 15% of the construction cost. Those savings can be added to contingency, reinvested in other priorities or returned to the client. The discipline lies in capturing them formally, implementing them through the design process, and making sure later design changes do not erode them.

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Construction Cost Control: Practical Disciplines

Beyond the formal reporting, effective construction cost control depends on a set of day-to-day disciplines.

Attend site regularly. A QS who does not visit site cannot understand the pace of the works, the complexity of what is being built, or the issues that are emerging. Site visits are not optional extras. They are the foundation of an accurate interim valuation and a credible cost report.

Attend design team and site progress meetings. Changes are born in meetings. The QS must be present when design decisions are made, so the cost implications are understood in real time. Otherwise they are discovered three months later when the instruction is issued.

Maintain a robust early warning system. Early warning is a formal requirement under NEC4, but it is good practice under any contract. Anyone on the project team who becomes aware of a matter that may affect cost, time or quality should raise it immediately. They should not sit on it in the hope it will resolve itself.

Challenge variations before they are instructed. The most cost-effective variation is the one that is never issued. When a change is proposed, the QS should provide a rapid cost assessment. They should consider whether the change is necessary, whether a cheaper alternative exists and whether the timing is right. A change instructed mid-construction almost always costs more than the same change made during design.

Do not allow the contingency to become a slush fund. Contingency is a specific provision for specific risks. It should be drawn down only with proper authorisation, against identified events, with a clear audit trail. A contingency consumed without discipline will run out before the project is complete. That leaves no reserve for the genuinely unforeseen events that always arise.

Report bad news early. A good commercial manager is willing to deliver uncomfortable information promptly. A cost overrun reported at £50,000 can be managed. The same overrun reported at £500,000, because the QS hoped it would go away, is a crisis. Clients, however difficult, deserve accurate and timely information.

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The Cost-Quality-Programme Triangle

Every project operates within the tension between cost, quality and programme. The three are interdependent. Compressing the programme typically increases cost. Reducing cost typically means reducing quality or extending the programme. Improving quality typically costs more money or takes more time.

The QS’s role in cost control is not simply to track numbers. It is to advise the client on the commercial consequences of decisions across all three dimensions.

• When the programme is accelerated to meet a commercial deadline, the client should understand exactly what that acceleration costs.
• When a specification is upgraded to improve quality, the budget impact should be quantified and approved before the change is instructed.
• When a scope reduction is proposed to save cost, the effect on function and quality should be clearly explained.

This advisory role is where the QS adds most value during construction. It means turning commercial data into information the client can use to make decisions. It is the difference between a cost controller who reports what has happened and a commercial manager who helps shape what will happen.

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Summary

Construction cost control and value management are not passive activities. They need active engagement with the project team and rigorous cost records. They also need the professional courage to report the financial position accurately, even when that position is uncomfortable.

The key principles to carry forward are these.

• Cost control is only as good as its baseline. A well-structured NRM 1 cost plan makes every later movement traceable.
• The cost report is the primary cost control instrument. It must be accurate, timely and written for the client’s decisions, not the QS’s convenience.
• The anticipated final account must reflect reality, not optimism. Unagreed and anticipated variations must be included at a realistic assessment.
• The variation log must be exhaustive and current. Every change is captured and every valuation status tracked.
• Earned value turns progress and cost data into a forecast. A CPI below 1.0 is an early signal that the final cost will exceed budget.
• Value engineering is not cost cutting. It is the systematic search for equivalent alternatives that deliver the same function at lower cost.
• Contingency must be managed as a controlled reserve, not a buffer against poor commercial discipline.
• Bad news must be reported early. The cost of delay is almost always greater than the cost of transparency.

In the next post in this series, we turn to dispute avoidance and resolution. It covers the mechanisms available when the parties cannot agree, from adjudication and arbitration through to the contractual and behavioural strategies that stop disputes arising in the first place.

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Frequently Asked Questions

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This series is written for quantity surveyors, project managers, construction professionals, and students in the built environment. Feedback and questions are welcome.