At a glance
Avg Scroll Depth % measures how far down the page visitors typically scroll, expressed as a percentage of the page height. FullStory captures scroll behaviour from the session timeline. It tells you whether your content below the fold is actually being seen. A low average means visitors stop near the top, so anything important, product details, reviews, calls to action, sat below the line is invisible to most of them. It is a layout and content-priority signal, not a frustration one.
| What it counts | The average maximum scroll depth reached per session, as a percentage of page height, captured by FullStory across the period. |
| Sample type | Backend API data from FullStory, refreshed on the standard data refresh. |
| Why it matters | It shows whether below-the-fold content is seen. Key information stranded past the average scroll depth is effectively invisible, which wastes the content and any conversion element living there. |
| Reading the value | Compare the current period to the prior period and read by template. A low value on a long page suggests moving important elements higher. |
| Currency | percent |
| Time window | 30D vsP |
| Alert trigger | - |
| Sentiment key | fs_scroll_depth_avg |
| Roles | owner, marketing |
Calculation
Calculated automatically from your FullStory data. Vortex IQ reads the maximum scroll position reached in each session, normalises it against page height, and averages it across sessions for the period. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading.Worked example
A representative reading of Avg Scroll Depth % for a typical merchant on FullStory. Suppose a long product page averages 38% scroll depth. The size guide and reviews, the two things shoppers ask for most, sit at 70% and 85%, so most visitors never reach them. Moving reviews up near the add-to-cart area lifts both scroll engagement and conversion. Without this card the buried content would have looked underused for no obvious reason. For deeper investigation, use Vortex Mind to compare scroll depth by template; for natural-language exploration, ask Ask Viq which pages people stop scrolling on.Sibling cards merchants should reference together
| Card | Why merchants reach for it |
|---|---|
fs_pages_per_session | A companion depth-of-engagement signal across pages. |
fs_worst_frustration_pages | Where shallow scrolling overlaps with frustration. |
fs_page_load_to_first_interaction | Slow pages can suppress scrolling. |
ful_avg_session_duration | A broader engagement companion. |
Reconciling against the vendor’s own dashboard
Where to look in FullStory’s own dashboard: FullStory exposes scroll behaviour through its heatmaps and page-level reporting. Confirm period boundaries and page scope match the Vortex IQ profile to reconcile cleanly. Why the Vortex IQ value may legitimately differ:| Reason | Direction | What to do |
|---|---|---|
| Page-height basis. Depth is relative to page height, which changes if a template was edited mid-period. | Variable | Check for layout changes in the window. |
| Period boundary. Vortex IQ uses 30-day rolling by default; FullStory dashboards may use calendar periods. | Variable | Match the period range. |
| Device mix. Mobile and desktop scroll very differently, so a shift in mix moves the average. | Variable | Check the device split. |