Why it matters to a buyer
Engagement rate is easy to confuse with bounce rate from Universal Analytics, but the two are built on different logic and are not directly comparable, so a buyer looking at a report spanning the transition between the two systems should not read a change in the number as evidence content quality actually changed. It is a genuinely useful proxy for whether content is actually being read or used, but it says nothing on its own about whether that engaged traffic converts into any business outcome.
How it is measured or applied
GA4 marks a session engaged automatically once it passes ten seconds, records a key event, or reaches a second page or screen view, and engagement rate is the share of total sessions meeting that bar. It is checked by landing page and by traffic source, since a low engagement rate on a specific page or channel points to a mismatch between what visitors expected and what the page delivered. It is read alongside conversion rate rather than instead of it, since a page can hold strong engagement without converting, or convert quickly without holding attention long.
Sources
- [GA4] Engagement rate, Google Analytics Help
