What Is Baseline Execution Index (BEI)? Schedule Health Metric

<div class="ge-article-wrapper"><article class="ge-article-body"><p>The Baseline Execution Index (BEI) measures how well the project is executing against its original baseline plan. While <a href="/en/earned-value/definitions/schedule-performance-index">SPI</a> tells you whether you're ahead or behind on the current plan, BEI tells you whether the current plan itself has drifted from the original baseline.</p><p>This term is part of the <a href="/en/earned-value/definitions">earned value definitions glossary</a>.</p><h2>The Formula</h2><div class="ge-formula-box ge-anim"><span class="ge-formula-label">Formula</span><code>BEI = (work packages completed on or before baseline date) / (work packages scheduled to be complete by baseline date)</code></div><p>BEI is a count-based metric, not a value-based one. It counts work packages, not pounds. A BEI of 0.85 means 85% of the work packages that should be done by now (per the original baseline) are actually done.</p><h2>BEI vs SPI: Why You Need Both</h2><pre class="ge-ascii-diagram ge-anim">SCENARIO: Project with re-baselined schedule Original baseline Current baseline completion: Month 18 completion: Month 22 SPI = 1.02 (ahead of CURRENT plan) BEI = 0.78 (behind ORIGINAL plan) SPI says: "We're fine" BEI says: "We've already slipped 4 months and re-baselined to hide it"</pre><h2>Worked Example</h2><span class="ge-worked-label">Worked Example</span><div class="ge-callout ge-anim"><p><strong>Scenario:</strong> A £25M NEC4 Option C water infrastructure project. At month 12, the original baseline shows 28 work packages should be complete. The current baseline (revised after programme updates) shows 22 should be complete. Actually complete: 21.</p><p>SPI (against current baseline) = 21/22 = 0.955. BEI (against original baseline) = 21/28 = 0.750.</p><p>SPI looks acceptable. BEI reveals the project is only 75% through what should have been done by now per the original plan.</p></div><h2>Common Mistakes</h2><ol><li><strong>Not tracking the original baseline separately.</strong> Once you re-baseline, keep the original for BEI calculation.</li><li><strong>Confusing BEI with SPI.</strong> They measure different things.</li><li><strong>Using BEI on projects that legitimately changed scope.</strong> BEI is most useful when scope is stable but schedule has drifted.</li></ol><div class="ge-product-note ge-anim"><p><strong>How Gather helps.</strong> Gather tracks progress against both original and current baselines automatically. <a href="https://gatherinsights.com/contact">Book a demo</a>.</p></div><h2>Frequently Asked Questions</h2><h3>What is a good BEI?</h3><p>Above 0.90 is healthy. Between 0.80 and 0.90 needs attention. Below 0.80 indicates significant baseline drift.</p><h3>Should BEI use work packages or activities?</h3><p>Work packages give a more stable metric. Activities are too granular and create noise.</p></article></div>