Ecommerce
Cart abandonment
Also called basket abandonment.
Cart abandonment is carts that received an item but never became a purchase. It is the share of shoppers who got partway and left.
How it is measured
Count carts with at least one add, then count those without a completed transaction in the window. Divide the second by the first. The window matters because some people finish tomorrow.
In Tarsier a cart that crosses midnight is not linked to its owner, so measure within one visit.
Worked example
A shoe shop's carts in July: 3,900 started, 1,060 purchased, so 73 percent abandoned. Exit surveys show the biggest reason is shipping cost revealed late. The shop shows shipping on the product page.
Carts started stay at 3,900, purchases rise to 1,310, and abandonment falls to 66 percent.
How it differs
Cart abandonment is a shop-specific ratio. Abandonment rate is the generic form. Add to cart is the start. Checkout step shows where in the path people leave.
Common errors
Counting visitors who never added. Treating all abandonment as lost sales. Ignoring recovery emails. Using a window that is too short. Comparing to benchmarks without matching definitions.
In practice
Look at where in checkout people leave first, then decide what to change.