Interview Questions › Metrics

Measure success of a "Buy Again" shelf in Instamart

Swiggy Instamart added a "Buy Again" shelf on the home screen showing items you bought before. What metrics would you use to judge it?

Context

Most Instamart baskets contain staple items bought every week. The shelf launched in Bengaluru two weeks ago.

Clarifying questions to ask first

• Is the main goal speed or basket size?
• Is this for all users or repeat buyers only?

How to approach it

1. Clarify the goal: faster checkout, bigger baskets or more frequent orders
2. Funnel: shelf view to tap to add-to-cart to order
3. Business outcome: order frequency and basket value
4. Guardrail: discovery of new items

Framework: Goal of the product -> Users and value exchange -> North Star -> Supporting metrics by funnel stage -> Guardrails and counter-metrics -> Decision or target

Sample answer

• Share of orders with at least one Buy Again item
• Median time from app open to order
• Weekly orders per active user

1. About 41% of orders now include a Buy Again item
2. Median time to checkout fell from 3m10s to 2m20s
3. New-item discovery (first-time SKUs per order) fell 9%

Primary: weekly orders per user, because the shelf exists to make reordering effortless. Supporting: shelf add-to-cart rate and time to checkout. Guardrail: first-time SKUs per order and average basket value, since the shelf can crowd out discovery.

What interviewers look for

• Shelf add-to-cart rate
• Time to checkout
• Orders per user per week