Microsoft·Data Scientist·Technical Phone Screen
Jul 2026
Microsoft data scientist technical screen, heavy SQL focus with some tricky edge cases built into the schema. Three-part question that escalated from a delivery rate calculation to a scenario-based switching analysis. Felt like a reasonable challenge but part (c) was a curveball I wasn't fully ready for.
- Given an Emails table and a Deliveries table, compute the proportion of emails delivered within 5 minutes of send time, grouped by provider and recipient domain, for emails sent in the last 7 days. Use the earliest delivered event, ignore spam_folder rows, and treat missing delivery records as undelivered. A bounce followed by a later delivery still counts if the delivered event falls within the 5-minute window.
- Return all message IDs where the first observed delivery event was a bounce and a subsequent delivered event happened more than 5 minutes after the original send time. Include the lag in minutes between send time and the first delivered event.
- For the ms.com domain over the same 7-day window, find the earliest calendar date where switching from Gmail to Outlook would have strictly improved deliverability. Base this on cumulative delivered-within-5-minutes rates up to and including each send date. Output the date and the cumulative rates that justify the switch.
“The spam_folder filter tripped me up first.”