What Is Discrete Effort in Earned Value? EV Measurement 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-three-types-of-effort">The Three Types of Effort</a></li> <li><a href="#why-discrete-effort-produces-better-data">Why Discrete Effort Produces Better Data</a></li> <li><a href="#the-80-20-rule">The 80/20 Rule</a></li> <li><a href="#worked-example-structural-steelwork-package">Worked Example: Structural Steelwork Package</a></li> <li><a href="#common-mistakes">Common Mistakes</a></li> <li><a href="#converting-loe-to-discrete-practical-tips">Converting LOE to Discrete: Practical Tips</a></li> <li><a href="#frequently-asked-questions">Frequently Asked Questions</a></li> </ul> </nav> <article class="ge-article-body"> <p>Discrete effort is work that produces a specific, measurable output, something you can point at and say "that's done" or "that's not done." In <a href="/en/earned-value">earned value management</a>, discrete effort is the gold standard for measuring progress because it's objective. You either erected the steel or you didn't.</p> <p>Compare that with Level of Effort (LOE), where progress is measured by time spent rather than output delivered. If you want your EVM data to mean anything, maximise the proportion of discrete effort in your work breakdown structure. The industry rule of thumb is 80/20: at least 80% discrete effort, no more than 20% LOE.</p> <p>This page is part of the <a href="/en/earned-value/definitions">earned value definitions glossary</a>.</p> <h2 id="the-three-types-of-effort">The Three Types of Effort</h2> <p>EVM recognises three types of effort: <strong>Discrete effort</strong> earns value based on measurable physical completion. <strong>Level of Effort (LOE)</strong> earns value based on time elapsed. <strong>Apportioned effort</strong> earns value based on another work package's progress.</p> <h2 id="why-discrete-effort-produces-better-data">Why Discrete Effort Produces Better Data</h2> <p>LOE work packages always show SPI of exactly 1.0 by definition. They're invisible to the warning system. If 40% of your BAC is in LOE work packages, 40% of your project is running on autopilot with no early warning capability.</p> <h2 id="the-80-20-rule">The 80/20 Rule</h2> <p>Aim for at least 80% of your BAC in discrete effort work packages. Cap LOE at 20%. On construction projects, this is achievable because most physical works are inherently discrete.</p> <h2 id="worked-example-structural-steelwork-package">Worked Example: Structural Steelwork Package</h2> <span class="ge-worked-label">Worked Example</span> <div class="ge-callout ge-anim"> <p><strong>Scenario:</strong> A £4.2M structural steelwork package on a £32M NEC4 Option A distribution centre. 1,850 tonnes of steel across three phases. At month 4: 680t erected of 1,850t planned.</p> <p>Physical % complete: 680/1,850 = 36.8%. EV = £4,200,000 x 0.368 = £1,545,600. SPI = 0.90. CPI = 0.96.</p> <p>The measurement is objective. 680 tonnes is 680 tonnes, verified by survey, not estimated by a project manager with a spreadsheet.</p> </div> <h2 id="common-mistakes">Common Mistakes</h2> <ol> <li><strong>Classifying physical works as LOE.</strong> If you can measure it, measure it.</li> <li><strong>Not reporting discrete and LOE performance separately.</strong></li> <li><strong>Using percentage complete estimates as "discrete" measurement.</strong></li> <li><strong>Ignoring the 80/20 rule.</strong></li> </ol> <h2 id="converting-loe-to-discrete-practical-tips">Converting LOE to Discrete: Practical Tips</h2> <p><strong>Design work:</strong> Measure by deliverable milestones. <strong>Commissioning:</strong> Measure by systems commissioned. <strong>Preliminaries:</strong> Apportion to the discrete packages they support.</p> <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 discrete effort and Level of Effort?</h3> <p>Discrete effort earns value based on measurable physical output. LOE earns value based on time elapsed. Discrete produces reliable SPI and CPI data. LOE always shows SPI of 1.0.</p> <h3>Why does LOE contaminate EVM data?</h3> <p>Because LOE work packages earn value automatically based on time, not output. When aggregated with discrete packages, they pull the overall SPI towards 1.0, masking real schedule slippage.</p> <h3>What's the ideal ratio of discrete to LOE?</h3> <p>80% discrete, 20% maximum LOE. In construction, aim for 85%+.</p> </article> </div>