Core Web Vitals are three specific performance metrics Google uses as ranking signals: Largest Contentful Paint (LCP, should be under 2.5s), Interaction to Next Paint (INP, under 200ms), and Cumulative Layout Shift (CLS, under 0.1). You measure them through Google Search Console's Core Web Vitals report, PageSpeed Insights, or Chrome DevTools, which show real-world data from actual users visiting your site. Start by identifying which pages fail these thresholds in Search Console. For LCP issues, optimize your largest above-fold element—usually a hero image or banner. Compress images to WebP format, use responsive sizing with srcset, enable CDN delivery, and preload critical assets. We've seen LCP drop from 4.2s to 1.8s just by switching a 1.2MB JPEG hero to a 180KB WebP and adding fetchpriority="high". INP replaced FID in March 2024 and measures how quickly your page responds to all user interactions, not just the first click. Fix it by reducing JavaScript execution time, breaking up long tasks, and deferring non-critical scripts. Heavy WordPress plugins and unoptimized tracking scripts are common culprits. CLS issues come from images without defined dimensions, ads that push content down, or web fonts that cause layout reflow. Set explicit width and height attributes on all images and reserve space for dynamic content. The tradeoff is effort versus impact. A site with 200-point mobile scores probably won't see ranking jumps from reaching 100, but a site stuck at 40 definitely will. At Ottawa SEO, we prioritize CWV fixes on high-traffic commercial pages first—your homepage and top-10 revenue generators—because that's where poor scores hurt conversions and rankings most. Monitor the Search Console report monthly, not daily, since the data reflects 28-day rolling averages. Core Web Vitals won't rescue terrible content, but they're table stakes for competitive queries where multiple sites have strong relevance signals.