What Is a Compensation Event Under NEC4? Complete EVM Guide

A compensation event (CE) under NEC4 is any event listed in clause 60.1 that entitles the Contractor to a change in the Prices, the Completion Date, or both. NEC4 ECC clause 60.1 lists 21 grounds, ranging from an instruction that changes the Scope to physical conditions that differ from what the Site Information described. In earned value management terms, every implemented CE changes your Budget at Completion (BAC) and reshapes your Planned Value baseline. Ignore that link, and your EVM data becomes noise.

This page is part of the earned value definitions glossary. For a deep dive into the NEC4 CE process itself, see the NEC4 compensation events guide.

The Core Mechanism

A compensation event isn't a variation. That distinction matters. Under JCT, you have variations. Under NEC4, you have compensation events. They look similar from a distance, but the mechanism is fundamentally different.

Under NEC4, the CE process works like this:

1. An event occurs (or an instruction is given)
2. The Contractor notifies the Project Manager within 8 weeks (clause 61.3)
3. The PM decides whether it's a CE
4. The Contractor submits a quotation (clause 62)
5. The PM accepts, negotiates, or makes their own assessment
6. The CE is implemented, Prices and programme adjust

Miss step 2 and the clause 61.3 eight-week time bar may prevent a change to the Prices or the Completion Date. It is not absolute. The bar does not apply where the event arises from the Project Manager giving an instruction or notification, issuing a certificate or changing an earlier decision, and it bites only on events the Contractor is obliged to notify. Establish the awareness date, the notification duty and any amendment before accepting that a notice is late.

How CEs Adjust the EVM Baseline

Here's where most commercial teams get it wrong. They track CEs in one system and EVM in another. The two never talk to each other.

When a CE is implemented under clause 65, the Prices change. On an Option C target cost contract, this means the target total of the Prices, your BAC, increases (or occasionally decreases). The Accepted Programme should also be updated to reflect any time impact.

That triggers a cascade through your entire EVM dataset:

 CE IMPLEMENTED │ ▼ ┌─────────────┐ ┌──────────────────────────┐ │ BAC changes │────▶│ PV baseline must be │ │ (Prices │ │ re-profiled against the │ │ adjusted) │ │ updated programme │ └─────────────┘ └──────────────────────────┘ │ │ ▼ ▼ ┌─────────────┐ ┌──────────────────────────┐ │ EV changes │ │ SPI recalculated against │ │ (new BAC in │ │ new PV baseline │ │ % complete) │ └──────────────────────────┘ └─────────────┘ │ ▼ ┌─────────────┐ ┌──────────────────────────┐ │ CPI changes │────▶│ EAC / ETC forecasts │ │ (EV / AC │ │ update automatically │ │ shifts) │ └──────────────────────────┘ └─────────────┘ 

If you don't feed implemented CEs into BAC, your CPI looks artificially low. You're measuring actual spend (which includes CE work) against the original budget (which doesn't). The project looks like it's haemorrhaging money when it's actually delivering additional scope that's been properly compensated.

The compensation events listed at clause 60.1

NEC4 ECC clause 60.1 lists 21 grounds. NEC3 listed 19, so a table copied from NEC3 material will be two short and may carry the older numbering and terminology. The selected main option, Contract Data, Scope and any Z clauses can add or alter grounds, so the executed contract is the only reliable list.

The grounds below are among those most commonly encountered, with numbering and wording following NEC4 ECC:

Glenn Hide of GMH Planning observes that an instruction changing the Scope under clause 60.1(1) probably accounts for at least half of the compensation events on most projects, with access under 60.1(2) and physical conditions under 60.1(12) among the other common grounds. That is practitioner experience rather than a measured distribution, so do not rely on a fixed percentage split or an expected number of events per project. For the full list and the exact wording, read GMH Planning’s guidance note on clause 60.1 alongside the contract itself.

Why EVM Data Supports Better CE Quotations

This is the bit most people miss. Your EVM data doesn't just get affected by CEs. It actively strengthens your CE quotations.

When you submit a quotation under clause 62, the PM is assessing whether your costs are reasonable. If you can show that your project-wide CPI is 0.95, that tells them your overall cost efficiency is strong. Any cost increase in the CE quotation is genuinely attributable to the compensable event, not to the Contractor's inefficiency.

Conversely, if your CPI is 0.78, expect the PM to push back. They'll argue (sometimes rightly) that some of the cost in your quotation reflects your own underperformance rather than the CE impact.

Strong EVM discipline is commercial ammunition. It separates CE costs from baseline inefficiency. That distinction is worth real money.

Worked Example: CE Adjusts BAC on a Rail Project

The Dividing Date and CE Assessment

CEs are assessed prospectively from the dividing date, the date the PM decides a CE is one, or should have decided. This matters for EVM because the assessment uses forecast costs from the dividing date forward, not historical actual costs.

Don't mix these up. The CE quotation is a prospective forecast. Your EVM tracks actual spend. The two converge over time as the CE work completes, but they start from entirely different reference points. I've seen QSs try to back-calculate a CE quotation from EVM actuals. That's wrong, and it'll get rejected.

Common Mistakes

1. Not updating BAC after CE implementation. The single most common mistake. Every implemented CE should trigger a BAC update on the same day. No exceptions. Set a process, make someone accountable, and check it monthly.

2. Tracking CEs in a separate spreadsheet from EVM. If your CE register and your EVM tracker are different files (or worse, managed by different people), they will diverge. Guaranteed. The CE register should feed directly into BAC.

3. Confusing CE notification with CE implementation. A notified CE doesn't change BAC. Only an implemented CE changes the Prices. You might have 15 notified CEs sitting in the pipeline. None of them should be in your BAC until the PM implements them. Track them as potential BAC adjustments in your EAC forecast, but keep them out of the baseline.

4. Forgetting the time impact in PV. A CE might add £500K to BAC and 4 weeks to the programme. If you update BAC but don't re-profile PV against the revised programme, your SPI is wrong. Both changes must flow through together.

5. Missing the 8-week time bar. This isn't an EVM mistake. It's a commercial catastrophe. If you don't notify within 8 weeks of becoming aware of the event, you lose the right to claim. That means no BAC adjustment, no time extension, and a genuine cost overrun eating into your margin.

Frequently Asked Questions

Does every CE change BAC?

Every CE that results in a change to the Prices will change BAC. Some CEs only affect the Completion Date (time but no cost). Others affect only cost. Most affect both. The key is implementation, until the CE is formally implemented under clause 65, BAC doesn't change. Notified CEs in the quotation pipeline are forecast adjustments, not baseline changes.

How do CEs affect CPI and SPI?

Once implemented, the CE increases BAC, which means your percentage complete (EV / BAC) drops slightly because the denominator has grown. As the CE work progresses and EV accumulates, it normalises. If you don't update BAC, CPI appears artificially low because actual cost includes CE work but the budget doesn't reflect it. SPI is affected through the programme update, the new Accepted Programme re-profiles PV.

What's the difference between a CE and a variation?

Under NEC4, there are no "variations." The compensation event mechanism replaces the traditional variation process found in JCT and other contract forms. CEs cover a broader range of events than traditional variations, they include not just changes to the works, but also Client failures, weather events, and physical conditions. The quotation process is also different: the Contractor proposes the cost and time impact, whereas under JCT, variations are typically valued using contract rates.

Can a CE reduce BAC?

Yes, but it's uncommon. A CE that removes scope (for example, the PM instructs deletion of a section of works under clause 60.1(1)) would reduce the Prices and therefore reduce BAC. In practice, most CEs increase BAC. A reduction is technically called a "negative compensation event" and follows the same quotation process.

Further reading from GMH Planning

Glenn Hide of GMH Planning publishes free NEC guidance notes, CECA bulletins and webinars. These explain the standard provisions and are useful alongside, not instead of, the executed contract:

• GMH guidance note: clause 60.1 compensation events
• GMH guidance note: notifying compensation events (clause 61)
• GMH/CECA bulletin 59: lack of response, time bars and deemed acceptances

Check the contract form, edition, incorporated amendments, main and secondary options, Contract Data and any Z clauses for your own project.