Items viewed is the number of items that the customer viewed.
Populate this metric by sending an items array with the 'view_item' event.
[Category] Ecommerce > Item scoped
When using Items viewed, other metrics such as Sessions decrease.
This is because Items viewed counts events where event_category is ecommerce.
If this situation is a problem, try using Item view events.
Item view events is the number of times the item details were viewed.
Populate this metric by sending an items array with the 'view_item' event.
[Category] Ecommerce > Event
Metrics such as Sessions can be preserved regardless of event_category.