Compensation Events

NEC Compensation Events: a practitioner guide to notification, quotation and assessment

Most NEC compensation events fail not because the law is hard, but because the discipline is. Here is what the clauses say, where the work breaks down, and what good looks like, written from live UK NEC contract administration.

27 April 2026 · 9 min read · Free to read

Executive summary

A compensation event is the contract’s only legitimate route to changing the agreed price, the agreed Completion Date, or a Key Date. Get the discipline wrong and you don’t just lose money: you lose the right to recover it.

This guide walks the clauses that actually run on live UK NEC contracts: 61 (notification), 62 (quotation), 63 (assessment) and 64 (the Project Manager’s assessment). Then it sets out where the work breaks down in practice, and what a senior commercial team looks like when it doesn’t.

Clause analysis

The compensation events clause analysis

Clause 61.1: when the PM notifies

The Project Manager notifies a compensation event at the time of giving an instruction or changing a decision that the contract treats as a CE. The notification is the trigger; the obligation to quote follows from it.

Clause 61.3: the eight-week time bar (and what it really means)

If the Contractor wants to notify a CE that the PM hasn’t already notified, it must do so within eight weeks of becoming aware of the event. Miss that window, and under NEC4 the Contractor is not entitled to a change in the Prices, the Completion Date or a Key Date for that event.

The trap is not the eight weeks. The trap is “became aware.” That date is provable from contemporaneous records: site diaries, EW registers, RFI logs, programme updates. If the records are tidy, the date is the date. If they aren’t, the PM gets to choose.

Clause 62: quotation

The Contractor submits a quotation showing the changes to the Prices and the Completion Date / Key Dates, with the assumptions stated. Three weeks is the default, often varied. The quotation must be reviewed within two weeks of submission.

Clause 63: assessment

Assessment is on the basis of the effect of the event on Defined Cost plus the Fee, with risk allowances and time impact added. Defined Cost references the Schedule of Cost Components (or the Short Schedule under shorter contracts). The shape of Defined Cost is what most disputes turn on.

Clause 64: PM assessment

If the Contractor doesn’t submit a quotation, or the PM decides the quotation isn’t a fair assessment, the PM assesses. The PM’s assessment is the Contractor’s assessment, that is the practical effect, unless and until challenged through the Adjudication route.

Commercial implications

What it means on a live programme.

On a live programme, the clauses above don’t run in tidy sequence. They run alongside an early-warning register that’s already three weeks behind, a programme that hasn’t been Accepted in two months, and a PM who is reading the quotation while another five quotations sit on their desk.

What that means: the timeline is shorter than the clauses suggest, the records are thinner than they should be, and the people doing the assessment are doing it under fatigue. The discipline that survives those conditions is what wins CEs. Everything else is a slow loss.

Failure modes

Where this fails in practice.

Late notification. The Contractor knew about the event in week one and notified in week ten. Time-barred under 61.3.
Notification with no event. A ten-line letter that doesn’t identify which clause 60.1 sub-paragraph the event sits under, doesn’t state the trigger date, and doesn’t describe the change. The PM rejects on form, not substance.
Quotation without assumptions. A quotation that bakes in three risk assumptions but states none of them. When the assumptions later prove wrong, there is no clause 61.6 hook to reopen.
Programme not impacted. A quotation showing cost change but no time impact, when the underlying programme logic clearly has float consumption. The PM accepts the cost; the Contractor loses the time.
No contemporaneous record. The cost build-up is reconstructed from invoices three months later. Defined Cost is challenged on the build-up, the build-up doesn’t hold, the assessment is reduced.
Silence on the PM’s assessment. The PM assesses under 64, the Contractor disagrees, and nothing is referred to Adjudication. The PM’s number becomes the contract number.

Key points

What good looks like.

One CE register, one source of truth. Every event tracked from the trigger date through to assessment, with the contemporaneous record reference attached.
Notifications drafted from a template that names the 60.1 sub-clause, the trigger, and the change. Three sentences. Nothing more.
Quotations that lead with assumptions. A short, numbered list of stated assumptions before the cost or time numbers. This is the 61.6 hook; protect it deliberately.
Cost build-ups that map back to the Schedule of Cost Components, not to the invoices. Defined Cost is a contractual definition, not an accounting one.
Programme impact assessed from the Accepted Programme using the contract’s float-ownership rules, not from the programme the team wishes existed.
A ten-day Adjudication-readiness check on every PM assessment. If the assessment under 64 is wrong, the Contractor decides within ten working days whether to refer. Silence loses by default.

Practical takeaway

The discipline that compounds.

The clause stack on compensation events is not the hard part. The hard part is that the contract is administered while the work is delivered, by people who are paid to deliver the work. The discipline that wins compensation events is the discipline of treating contemporaneous record-keeping as a delivery activity, not a back-office one.

Future posts in this theme will go deeper on each clause: quotation drafting, the SCC, programme impact, and the adjudication-readiness loop. Subscribe to get the next post the morning it ships.