What Is an Activity Schedule in NEC4? EVM Pricing Guide

<div class="ge-article-wrapper"><nav class="ge-toc" aria-label="Table of contents"><p class="ge-toc-label">In this article</p><ul class="ge-toc-list"><li><a href="#the-definition">The Definition</a></li><li><a href="#how-the-activity-schedule-maps-to-evm">How the Activity Schedule Maps to EVM</a></li><li><a href="#the-payment-mechanism-on-nec4-option-a">The Payment Mechanism on NEC4 Option A</a></li><li><a href="#the-granularity-problem">The Granularity Problem</a></li><li><a href="#worked-example-building-an-activity-schedule-for-evm">Worked Example: Building an Activity Schedule for EVM</a></li><li><a href="#common-mistakes">Common Mistakes</a></li><li><a href="#frequently-asked-questions">Frequently Asked Questions</a></li></ul></nav><article class="ge-article-body"><p>An activity schedule is a list of activities the Contractor expects to carry out, each with a lump sum price. Under NEC4 Options A and C, it's the pricing document, the thing that determines how much the Contractor gets paid and when. But it's also, if you set it up properly, the foundation of your entire <a href="/en/earned-value">earned value management</a> system. Most teams treat the activity schedule as an admin exercise. That's a £500K mistake waiting to happen.</p><p>The activity schedule sits within the <a href="/en/earned-value/definitions">earned value definitions glossary</a>. For how it feeds into the three core EVM metrics, see the <a href="/en/earned-value/formulas">earned value formulas page</a>.</p><h2 id="the-definition">The Definition</h2><div class="ge-formula-box ge-anim"><span class="ge-formula-label">Formula</span><code>Activity schedule = a list of activities, each priced as a lump sum, which together make up the total of the Prices.</code></div><p>On NEC4 Option A (priced contract with activity schedule), payment is tied directly to completed activities. You don't get paid for 80% of an activity. You get paid when it's done. Full stop. On Option C (target contract with activity schedule), the activity schedule defines the target, the number against which the pain/gain mechanism operates.</p><p>The critical distinction: an activity schedule isn't a programme. It's a pricing document. Activities on the schedule don't need to match activities on the programme, though aligning them makes life dramatically easier.</p><h2 id="how-the-activity-schedule-maps-to-evm">How the Activity Schedule Maps to EVM</h2><p>This is where the activity schedule becomes powerful. Each activity on the schedule has a price. That price, when mapped against the programme timeline, becomes your time-phased budget, and that's your <a href="/en/earned-value/definitions/planned-value">Planned Value</a> curve.</p><pre class="ge-ascii-diagram ge-anim"> ACTIVITY SCHEDULE PROGRAMME PV CURVE ┌──────────────────────┐ ┌──────────────────────┐ £ (cumulative) │ Activity │ Price │ │ Activity │ Duration │ │ ├───────────┼──────────┤ ├───────────┼──────────┤ 15M ─┤ ╱─── BAC │ Piling │ £2.1M │ │ Piling │ M1 - M3 │ │ ╱╱ │ Substruc. │ £3.4M │ │ Substruc. │ M2 - M5 │ 10M ─┤ ╱╱╱ │ Frame │ £4.2M │ │ Frame │ M4 - M8 │ │ ╱╱╱ │ Envelope │ £2.8M │ │ Envelope │ M7 - M10 │ 5M ─┤ ╱╱╱ │ Fit-out │ £1.5M │ │ Fit-out │ M9 - M12 │ │ ╱╱ │ Externals │ £1.0M │ │ Externals │ M10- M12 │ 0 ──┼────────────────────── └───────────┴──────────┘ M1 M3 M6 M9 M12 │ TOTAL │ £15.0M │ └───────────┴──────────┘ Price + Duration = PV at any date </pre><p>Each activity's price gets spread across its programme duration. Sum them cumulatively and you've got the S-curve. That's your <a href="/en/earned-value/definitions/planned-value">Planned Value</a> baseline, the line every other EVM metric is measured against.</p><h2 id="the-payment-mechanism-on-nec4-option-a">The Payment Mechanism on NEC4 Option A</h2><p>On Option A, payment works on a binary basis. An activity is either complete or it isn't. Clause 11.2(29) defines the Price for Work Done to Date (PWDD) as the total of the prices for completed activities.</p><p>This matters for EVM because it forces a natural alignment. If you've structured the activity schedule with enough granularity, the PWDD is effectively your <a href="/en/earned-value/definitions/earned-value">Earned Value</a>. Activity complete? It's earned. Activity not complete? It's not. Clean, simple, binary.</p><p>The problem arises when activities are too big. "Structural concrete, £2.4M" as a single activity means you earn nothing until all the concrete is done. That's months of work with zero EV recognition. Your <a href="/en/earned-value/definitions/schedule-performance-index">SPI</a> looks catastrophic even when progress is fine.</p><h2 id="the-granularity-problem">The Granularity Problem</h2><p>This is the single most common issue I see with activity schedules. Teams set them up with 15 to 20 activities on a £15M project. Each activity covers months of work and hundreds of thousands of pounds. From a payment perspective, that's brutal. From an EVM perspective, it's useless.</p><p>Here's the rule I use: no activity should exceed 2% of the total contract value, and no activity should span more than two assessment periods. On a £15M contract, that means activities capped at around £300K and no longer than 8 weeks' duration.</p><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Granularity Level</th><th>Activities (£15M contract)</th><th>Max Activity Value</th><th>EVM Quality</th></tr></thead><tbody><tr><td>Coarse</td><td>10 - 15</td><td>£1.5M+</td><td>Poor, massive EV steps, no early warning</td></tr><tr><td>Moderate</td><td>30 - 50</td><td>£300K - £500K</td><td>Good, monthly EV recognition, reasonable S-curve</td></tr><tr><td>Fine</td><td>80 - 120</td><td>£125K - £190K</td><td>Excellent, smooth PV curve, early variance detection</td></tr><tr><td>Excessive</td><td>200+</td><td>< £75K</td><td>Diminishing returns, admin burden outweighs insight</td></tr></tbody></table></div><p>On one HS2 subcontract I worked on, the activity schedule had 12 activities for £22M of earthworks. The commercial team couldn't produce a meaningful EV report for the first four months because nothing was "complete." We restructured it into 65 activities, same total price, same scope, and suddenly EVM actually worked. It took the QS two days. Should've been done at tender stage.</p><h2 id="worked-example-building-an-activity-schedule-for-evm">Worked Example: Building an Activity Schedule for EVM</h2><span class="ge-worked-label">Worked Example</span><div class="ge-callout ge-anim"><p><strong>Scenario:</strong> Murphy Group is delivering a £15M NEC4 Option A highways improvement scheme on the A38 near Derby. The commercial manager needs to set up the activity schedule to support both payment and earned value tracking.</p><p><strong>Step 1: Define work packages</strong></p><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Work Package</th><th>Budget</th><th>Duration</th></tr></thead><tbody><tr><td>Traffic management</td><td>£1,200,000</td><td>M1 - M10</td></tr><tr><td>Earthworks</td><td>£2,800,000</td><td>M1 - M5</td></tr><tr><td>Drainage</td><td>£1,600,000</td><td>M3 - M6</td></tr><tr><td>Pavement layers</td><td>£4,200,000</td><td>M5 - M9</td></tr><tr><td>Structures (2 bridges)</td><td>£3,100,000</td><td>M2 - M8</td></tr><tr><td>Finishing works</td><td>£1,400,000</td><td>M8 - M11</td></tr><tr><td>Landscaping</td><td>£700,000</td><td>M9 - M12</td></tr><tr><td><strong>Total</strong></td><td><strong>£15,000,000</strong></td><td><strong>12 months</strong></td></tr></tbody></table></div><p><strong>Step 2: Break into EVM-friendly activities (target: 30-50)</strong></p><p>The QS breaks "Earthworks" (£2.8M over 5 months) into 8 activities:</p><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Activity</th><th>Price</th><th>Programme Period</th></tr></thead><tbody><tr><td>Topsoil strip, Ch 0+000 to 1+500</td><td>£320,000</td><td>M1 - M2</td></tr><tr><td>Topsoil strip, Ch 1+500 to 3+000</td><td>£340,000</td><td>M2 - M3</td></tr><tr><td>Cut to fill, Section A</td><td>£480,000</td><td>M2 - M3</td></tr><tr><td>Cut to fill, Section B</td><td>£520,000</td><td>M3 - M4</td></tr><tr><td>Imported fill, Area C</td><td>£380,000</td><td>M3 - M5</td></tr><tr><td>Subgrade preparation, Phase 1</td><td>£290,000</td><td>M4 - M5</td></tr><tr><td>Subgrade preparation, Phase 2</td><td>£270,000</td><td>M4 - M5</td></tr><tr><td>Earthworks acceptance testing</td><td>£200,000</td><td>M4 - M5</td></tr></tbody></table></div><p><strong>Step 3: Derive PV</strong></p><p>With 8 activities spread across months 1 to 5, the earthworks PV curve builds smoothly:</p><ul><li>End of M1: £160,000 (half of topsoil strip activity 1)</li><li>End of M2: £820,000 (topsoil 1 complete, half of topsoil 2 + cut A started)</li><li>End of M3: £1,660,000</li><li>End of M4: £2,460,000</li><li>End of M5: £2,800,000 (earthworks BAC)</li></ul><p>Repeat for all seven work packages. The sum across all packages at any date is the project PV.</p><p><strong>Result:</strong> 38 activities across the full schedule, with the largest single activity at £420,000 (2.8% of contract value). Granular enough for monthly EVM, manageable enough that the QS doesn't spend their life updating a spreadsheet.</p></div><h2 id="common-mistakes">Common Mistakes</h2><ol><li><strong>Treating the activity schedule as a bill of quantities.</strong> It's not. Activities are lump sums for defined scope, not measured quantities. Don't put "concrete m3" on an activity schedule, put "pour basement slab, Block A."</li><li><strong>Not aligning activities with the programme.</strong> If Activity 7 on the schedule doesn't map to any activity on the programme, you can't derive PV for it. The schedule and programme don't need to be identical, but every priced activity needs a programme duration.</li><li><strong>Front-loading the activity schedule.</strong> Some contractors price early activities high and late activities low to improve cash flow. Clever commercially, but it distorts PV and makes EVM meaningless. A front-loaded PV curve will show artificially good SPI in early months and horrific SPI later, even if progress is perfectly on track.</li><li><strong>Forgetting to update after compensation events.</strong> On NEC4, an implemented CE changes the activity schedule (clause 65.4 on Option A). If you don't add the new activities or adjust existing ones, your <a href="/en/earned-value/definitions/budget-at-completion">BAC</a> is wrong and every EVM metric downstream is fiction.</li></ol><div class="ge-product-note ge-anim"><p><strong>How Gather helps.</strong> Gather's AI reads your site diaries daily and maps progress against your cost-loaded programme, giving you accurate earned value data without manual spreadsheet updates. <a href="https://gatherinsights.com/contact">Book a demo</a> to see it working on a live NEC4 project.</p></div><h2 id="frequently-asked-questions">Frequently Asked Questions</h2><h3>What's the difference between an activity schedule and a bill of quantities?</h3><p>A bill of quantities prices measured items (e.g., 450 m3 of concrete at £185/m3). An activity schedule prices lump sum activities (e.g., "pour ground floor slab, £83,250"). On NEC4, Option A uses an activity schedule; Option B uses a bill of quantities. For EVM, activity schedules are generally easier to work with because the lump sum price maps directly to earned value, complete the activity, earn the value.</p><h3>Can you change the activity schedule after contract award?</h3><p>Yes, but only through defined mechanisms. On NEC4, the Contractor can propose changes to the activity schedule (clause 54.2) provided the total doesn't change. Compensation events add new activities or adjust existing ones. You can't unilaterally restructure it, changes need the Project Manager's acceptance.</p><h3>How many activities should an activity schedule have?</h3><p>There's no contractual rule. For EVM purposes, I'd aim for one activity per 1.5% to 3% of the contract value, spanning no more than two assessment periods each. On a £15M contract, that's 35 to 65 activities. Enough for a smooth PV curve, not so many that you drown in admin. The sweet spot depends on your programme structure and how many distinct work fronts you're running.</p><h3>How does the activity schedule work on NEC4 Option C?</h3><p>On Option C, the activity schedule defines the target. Not the payment mechanism. Payment is based on Defined Cost (actual cost) plus fee. But the activity schedule still sets <a href="/en/earned-value/definitions/budget-at-completion">BAC</a> and, when cost-loaded against the <a href="/en/earned-value/definitions/accepted-programme">Accepted Programme</a>, produces the PV baseline. The pain/gain share at project end compares total Defined Cost against the target total of the Prices from the activity schedule.</p></article></div>