What Is a Control Account in EVM? Project Controls Explained

<div class="ge-article-wrapper"><article class="ge-article-body"><p>A control account is the management control point where scope, budget, and schedule are integrated and where <a href="/en/earned-value">earned value</a> performance is measured. It sits at the intersection of the <a href="/en/earned-value/definitions/work-breakdown-structure">Work Breakdown Structure</a> (WBS) and the <a href="/en/earned-value/definitions/organisational-breakdown-structure">Organisational Breakdown Structure</a> (OBS).</p><p>This term is part of the <a href="/en/earned-value/definitions">earned value definitions glossary</a>.</p><h2>How Control Accounts Work</h2><pre class="ge-ascii-diagram ge-anim">CONTROL ACCOUNT = WBS x OBS INTERSECTION WBS │ Project ├── Phase 1 │ ├── Earthworks ────┬───── CA-101 │ ├── Drainage ─────┬───── CA-102 │ └── Pavement ─────┬───── CA-103 ├── Phase 2 │ │ │ │ OBS │ │ │ Civils Mgr Drainage Mgr │ (owns CA-101, (owns CA-102) │ CA-103) Each CA has: Scope + Budget + Schedule + Owner</pre><h2>Control Account Structure</h2><div class="ge-table-wrap ge-anim"><table class="ge-table"><thead><tr><th>Element</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td>Scope</td><td>WBS elements assigned</td><td>All earthworks activities</td></tr><tr><td>Budget</td><td>BAC for this CA</td><td>£2,800,000</td></tr><tr><td>Schedule</td><td>Start/finish from programme</td><td>M1 to M5</td></tr><tr><td>Owner</td><td>Control Account Manager</td><td>Civils Manager</td></tr></tbody></table></div><h2>Worked Example</h2><span class="ge-worked-label">Worked Example</span><div class="ge-callout ge-anim"><p><strong>Scenario:</strong> A £28M NEC4 Option C infrastructure project with 12 control accounts.</p><p>CA-103 (Pavement): Budget £4.2M, Month 7 EV = £2.1M, AC = £2.4M. CPI = 0.875. This CA is driving the project-level cost overrun.</p><p>Without CA-level tracking, you'd see project CPI = 0.95 and think everything was manageable. The CA drill-down reveals one package is in serious trouble.</p></div><h2>Common Mistakes</h2><ol><li><strong>CAs too large.</strong> If a CA spans 6+ months and £5M+, you lose early warning capability.</li><li><strong>No single owner.</strong> Every CA needs one accountable person.</li><li><strong>CAs not aligned to NEC4 activity schedule.</strong></li></ol><div class="ge-product-note ge-anim"><p><strong>How Gather helps.</strong> Gather maps site diary progress to control accounts automatically. <a href="https://gatherinsights.com/contact">Book a demo</a>.</p></div><h2>Frequently Asked Questions</h2><h3>How many control accounts should a project have?</h3><p>Typically 10-30 for a £20-50M project. Enough for meaningful drill-down, not so many that management becomes admin.</p></article></div>