Change Order vs Variation vs Compensation Event: A Contractor's Plain-English Guide

In construction, a change order and a variation order do the same job under two names: the formal document that changes the contracted work and adjusts the price, the time or both. Change order is the North American and bespoke-contract term. Variation order is the UK, Commonwealth and FIDIC-derived term. NEC replaces both with the compensation event, which also covers employer-risk events that change no scope at all.

Most project teams use the three terms interchangeably, and on site that rarely matters. In the commercial office it does, because each label carries its own trigger, pricing basis and clock. The question is not what the site calls the change but what the contract calls it.

Change order vs variation order: is there a real difference?

In function, no. The differences that matter come from the contract form behind the label, and above all from whether that form treats the change as an agreement or as an instruction.

Under the AIA A201 general conditions used widely in the United States, a change order is a written instrument signed by the owner, the contractor and the architect. It records their agreement on the change in the work and on any adjustment to the contract sum and the contract time. Where agreement fails, the owner can direct the change by a construction change directive and settle the adjustment afterwards.

FIDIC works the other way round. The Engineer instructs a Variation under Clause 13, the contractor is bound to carry it out, and price and time are agreed or determined afterwards. 'Variation order' is not a defined FIDIC term. It is the industry's name for the document carrying the instruction, used on FIDIC-based and bespoke projects across the Middle East, Africa and Asia alike.

Employer-drafted contracts borrow from both vocabularies, and some define a change order as a document that binds only once both parties sign it. That one drafting choice moves the pricing risk to the contractor, because work started before signature may sit outside the contract altogether.

Compensation event vs variation: what is the difference?

The difference is reach and timing. A FIDIC variation is a change to the Works instructed or approved under Clause 13, valued under the contract's own rules and often after the work is done. An NEC compensation event is any event the contract lists, chiefly in clause 60.1, that can change the Prices or the Completion Date, a Scope change being only one of them, and it is priced prospectively, from the dividing date forward, in one quotation covering time and money.

Breadth is the first difference. NEC4 lists twenty-one compensation events in clause 60.1 alone. They include the Client failing to provide something on time, physical conditions an experienced contractor would have judged too unlikely to allow for, and weather rarer than once in ten years.

Under the FIDIC Red and Yellow Books these are not Variations. They are claims under Clause 20.1 in the 1999 editions or Clause 20.2 in the 2017 editions, which require notice within 28 days after the contractor became aware, or should have become aware, of the event. The 2017 editions add a fully detailed claim within 84 days. Exceptionally adverse climatic conditions earn an extension of time under the Red and Yellow Books but no extra money, and the Silver Book leaves both weather and unforeseeable physical conditions with the contractor, while NEC pays for weather beyond its ten-year measure.

Pricing differs too. NEC prices the effect of the event on Defined Cost plus the Fee, much of it forecast. The FIDIC Red Book starts from the contract rates and moves to new rates only where they do not fit. A low tender rate therefore tends to follow a contractor into its FIDIC variations. Under NEC the change is costed on its own terms unless the parties agree to use rates.

Time and notice follow the same split. An NEC quotation states both the change to the Prices and any delay to the Completion Date, and a contractor-notified event must be notified within eight weeks of awareness. An instructed FIDIC Variation needs no claim notice under the 2017 editions, while the 1999 editions send its extension of time through the Clause 20.1 claim procedure.

Change order vs variation vs compensation event side by side

The table compares the three on the points that decide payment.

How does a FIDIC Clause 13 variation work?

The Engineer may initiate a Variation before the Taking-Over Certificate, either by instruction or by first requesting a proposal. The contractor is bound by an instructed Variation unless it promptly objects on the limited grounds listed, such as being unable to readily obtain the goods required. FIDIC's 2017 Red Book adds grounds including varied work that was Unforeseeable given the scope and nature of the Works, and work affecting health, safety or environmental obligations.

Under the 2017 Red and Yellow Books, Sub-Clause 13.3.1 requires the contractor to proceed with the work. Within 28 days of the instruction it submits particulars of the work, its programme and the proposed adjustments to time and price. The Engineer then agrees or determines both under Sub-Clause 3.7, valuing Red Book work under Clause 12 as explained in valuing variations under FIDIC. Across the 2017 editions, Sub-Clause 8.5 grants the related extension of time without a Clause 20.2 notice. If the contractor does not dispute that determination by a Notice of Dissatisfaction within 28 days, it becomes final and binding.

The 1999 editions are less forgiving. The extension of time for a Variation sits in Sub-Clause 8.4, subject to Clause 20.1 and its 28-day notice unless the time adjustment was agreed within the Variation. A contractor can be paid for the extra work and still face delay damages for the time it took.

The larger trap is the instruction nobody calls a Variation. Sub-Clause 3.5 of the 2017 Red and Yellow Books requires a contractor who considers an instruction to be a Variation to give Notice immediately and before starting the work. If the Engineer does not confirm, reverse or vary the instruction within 7 days, it is treated as revoked. If the Engineer confirms it, the contractor must comply and should give a Clause 20.2 Notice of Claim straight away, because the 28-day clock may already be running, and our guide on how to notify a variation under FIDIC sets out each notice.

How does an NEC compensation event work?

NEC4 channels the contractor's entitlement to more time and money through compensation events, and NEC's own introduction to compensation events stresses that entitlement depends on notification. The Project Manager notifies events that arise from its own or the Supervisor's instructions, notifications, certificates or changed decisions. The contractor notifies the rest within eight weeks of becoming aware that the event has happened (clause 61.3), or the Prices and the Completion Date do not change.

The Project Manager replies to a notification within one week (clause 61.4). The contractor then quotes within three weeks of the instruction, and the Project Manager replies within two weeks (clause 62.3). If the Project Manager stays silent, the contractor may notify that failure, and two further weeks of silence count as acceptance (clause 62.6). A silent Project Manager can therefore hand the contractor its own price.

The quotation is prospective. It combines actual Defined Cost before the dividing date with forecast Defined Cost after it, plus the Fee (clause 63.1), and measures delay against planned Completion on the Accepted Programme. Once implemented, it is not revised because a forecast proves wrong, unless the contract provides otherwise, for example where a Project Manager assumption proves wrong and is corrected as a new compensation event (clause 66.3). Because the contractor keeps any saving and carries any overrun, the quotation should include allowances for risks that have a significant chance of occurring and are at the contractor's risk, as our guide to what is a compensation event under NEC explains.

What happens to a change nobody processes?

Each procedure has a default, and the default decides where the money ends up. Under NEC, an event the contractor should have notified but did not within eight weeks changes nothing. A notified event without a quotation is assessed by the Project Manager under clause 64.1. Under FIDIC, an instructed Variation is still valued, but an unrecognised instruction can leave the work inside the original price, and under the 2017 editions the Engineer's determination of that value becomes final and binding unless a Notice of Dissatisfaction is given within 28 days. Under a bespoke clause that requires a signed change order first, unsigned work may not be payable under the contract at all. The governing law may still allow recovery outside the contract, for example on a quantum meruit basis, but that route is slower and less certain.

The problem is rarely entitlement. It is the clock. A change can be instructed, built and accepted on site and still be commercially lost. On a QAR 60 million contract carrying forty instructed changes, the final account is either argued from contemporaneous notices or rebuilt from memory. Working every date back from the event with our notice deadline calculator keeps the first option open.

How should you manage change across FIDIC, NEC and bespoke contracts?

Start with the contract, not the site vocabulary. On day one, record which suite and edition applies, what triggers the change procedure, which clock starts and how the change is priced, then build the register around those answers. A FIDIC register tracks instructions and determinations, while an NEC register tracks notifications, quotation deadlines and dividing dates, as our guide to variations and change management sets out.

We review hundreds of variation and change submissions every year. On mixed portfolios the pattern is consistent. Teams apply the procedure they know best to every contract, the trap our comparison of NEC vs FIDIC warns about, and the result is missed eight-week windows on NEC work and unrecognised instructions on FIDIC work.

At CALIM, we map the change procedure for each contract before the first instruction arrives, then run variation management against that map until the final account is agreed.

Frequently Asked Questions

What is the difference between a change order and a variation order?

There is no difference in function. Both are the formal document that changes the contracted work and adjusts the price, the time or both. Change order is the North American and bespoke-contract term, used in the AIA A201 general conditions. Variation order is the UK, Commonwealth and international name for the document carrying a variation, including a FIDIC Clause 13 Variation. The procedure always comes from the contract, not the name on the form.

What is the difference between a compensation event and a variation?

A variation is a change to the Works instructed under FIDIC Clause 13. A compensation event is an event the NEC contract lists as one, including the twenty-one in NEC4 clause 60.1, that can change the Prices and the Completion Date. A Scope change is only one of them. Unforeseen physical conditions and exceptional weather are compensation events under NEC but Clause 20 claims under the FIDIC Red and Yellow Books, and largely the contractor's risk under the Silver Book. Compensation events are also priced prospectively, in one quotation covering both time and money.

Does an instructed FIDIC variation need a notice of claim for time?

Under the 2017 FIDIC editions, not for the Variation itself. It is valued under Sub-Clause 13.3.1, and Sub-Clause 8.5 grants the related extension of time without a Clause 20.2 Notice of Claim. Two clocks still run. Dispute the Engineer's determination by a Notice of Dissatisfaction within 28 days or it becomes final and binding, and notify knock-on disruption to unchanged work under Clause 20.2 as a precaution. Under the 1999 editions the extension of time for a Variation needs a Clause 20.1 notice within 28 days unless it was agreed within the Variation. An unlabelled instruction needs Notice immediately under 2017 Sub-Clause 3.5, or a Clause 20.1 notice under 1999.

What happens if I miss the eight-week time bar for an NEC compensation event?

If you miss the eight-week window after becoming aware of the event, NEC4 clause 61.3 provides that the Prices, the Completion Date and any Key Date do not change. On its terms you lose the time and the money, however genuine the event, though how strictly a tribunal applies the bar depends on the governing law. The eight weeks run from awareness of the event itself, not from realising it is a compensation event. The bar does not apply to events arising from the Project Manager or Supervisor giving an instruction or notification, issuing a certificate or changing an earlier decision. Check the Z clauses too, which can change the period.

Do I need a signed change order before starting extra work?

It depends on the contract. Under AIA A201 the owner can direct the work by construction change directive before the price is agreed. Under FIDIC the contractor must carry out an instructed Variation and the price follows. Many employer-drafted contracts make written approval a condition of payment, so work done on a verbal instruction can go unpaid. If you must proceed before signature, confirm the instruction in writing the same day.

Because the change that follows the wrong procedure is the change nobody pays for.

Note: This article is general information on change procedures under FIDIC, NEC and bespoke contracts, not legal advice. Notice periods and valuation rules vary by edition and amendment, so check your particular conditions before acting on a change.