A follow-up rarely wins a job but occasionally saves one, particularly when you fumbled a question.
The structure
1. Thanks for the time, naming the role
2. One specific reference to something discussed — proves you listened
3. One addition: a better answer to a question you handled poorly, or a link to relevant work
4. A clear statement that you want the job
Send within a day
After 48 hours the decision is often made. Same day is better than polished.
Use the clarification slot properly
If you gave a weak answer, this is the one chance to improve it. Two sentences, no apology, just the better answer.
Common questions
Do thank-you emails actually matter?
Sometimes. They matter most when they fix a weak answer or add relevant evidence.
Should I email every interviewer?
Email the person who scheduled it and ask them to pass on thanks, or email each individually if you have their addresses.