CRO Glossary
Quick, jargon-free definitions you can skim in under three minutes.
A/B Test - An experiment that splits traffic between two versions of a page (A = control, B = variant) to see which converts better.
Above the Fold - The portion of a web page visible without scrolling; prime real estate for headlines and CTAs.
Bounce Rate - The percentage of visitors who leave after viewing only one page; high bounces often signal message mismatch or slow load times.
Confidence Level - The probability (e.g., 95 %) that the observed conversion lift isn’t due to random chance.
Conversion Funnel - The step-by-step path users follow from initial visit to final action (e.g., landing page → product page → checkout).
Conversion Rate (CVR) - Conversions ÷ total visitors × 100; core metric CRO seeks to improve.
Control: The original, unaltered version of a page in an experiment.
CTA (Call-to-Action) — A button or link that tells visitors the next step, such as “Buy Now” or “Start Trial.”
CRO (Conversion Rate Optimisation) — The discipline of increasing the percentage of visitors who complete a desired action through research, design changes, and testing.
CTR (Click-Through Rate) — Clicks on a link or ad ÷ impressions × 100; gauges headline or ad copy effectiveness.
Heatmap - A visual overlay that shows aggregate user clicks, taps, or scroll depth on a page.
Hypothesis - A testable statement predicting how a change will affect a metric: “If we do X, Y will improve because Z.”
ICE Score — A quick-prioritisation framework: Impact, Confidence, Ease (1–5 each); higher totals get tested first.
Largest Contentful Paint (LCP) — A Core Web Vital measuring how long the biggest element takes to load; target < 2.5 s.
Lift — The percentage improvement of a variant over the control (e.g., +12 % CVR).
Macro Conversion: A primary goal tied directly to revenue, like a completed purchase or booked demo.
Micro Conversion: A smaller, supportive action—newsletter signup, add-to-cart—that signals progress toward a macro goal.
Page Speed — How quickly a page loads and becomes interactive; a key driver of both UX and SEO.
Personalisation — Dynamically changing page content for different user segments (geo, device, traffic source).
Sample Size — The minimum number of visitors or conversions needed per variant to reach statistical significance.
Scroll Depth — How far down the page users typically scroll; helps locate content drop-off points.
Segmentation — Breaking data into subsets (device type, traffic source, new vs. returning) to uncover hidden patterns.
Session Replay: A video-like playback of an individual user’s journey, revealing hesitation or error moments.
Statistical Significance (p-value): A calculation that shows whether a test result is likely real; p < 0.05 = 95 % confidence.
Trust Badge: A security or guarantee icon (SSL lock, “30-Day Refund”) placed near CTAs to reduce purchase anxiety.
UX (User Experience): The overall ease, clarity, and satisfaction a visitor feels while interacting with a site.
Variant: Any alternative version of a page or element being tested against the control.
Visual Hierarchy: The arrangement of design elements to guide the eye toward what matters most typically headline, benefit, CTA.
Pin this glossary next to your testing scorecard and you’ll keep every stakeholder—from designer to CEO speaking the same CRO language.