The scroll event in GA4 Enhanced Measurement operates based on a single threshold (90%). In other words, when the user scrolls to 90% of the page, the scroll event is fired once, and no additional events are fired even if the user scrolls again on the same page. The value 90 is sent as the percent_scrolled parameter.
To measure scroll depth in UA, we had to set up a scroll depth trigger in GTM and create events for the 25%, 50%, 75%, and 100% thresholds. GA4 Enhanced Measurement automates this task to a single 90% threshold. If you need more detailed scroll depth (25%, 50%), set it as an additional custom event in GTM.
GA4 screen path: Management → Data Stream → Enhanced Measurement → ‘Scroll’ can be turned on and off with the toggle. You can check the number of scroll events in the Report → Event tab, or analyze users who scrolled by page based on scroll events in Explorations.
weballin's practical perspective: If the scroll event is low on a long procedure detail page or blog content, it is a sign that there is a lot of abandonment at the beginning of the content. Pages with a low scroll reach rate are used as a basis for moving key content to the top or improving the content structure.
Key takeaways
- It is triggered only once when the page is scrolled more than 90%, and the percent_scrolled: 90 parameter is sent together.
- GA4 Enhanced Measurement is activated with a single toggle and requires no additional coding.
- If you need detailed thresholds such as 25%, 50%, or 75%, add a custom event with the GTM scroll depth trigger.
- You can measure the quality of content consumption by calculating the scroll reach rate compared to page views.
- In UA, GTM required separate settings, but in GA4, it is provided as a built-in function.