I had 2 interviews with 2 different individuals and then had to do an assignment. After my assignment, I did not hear back from anyone for up to three weeks. It was only until I reached out that I learned I did not get the job. Interviewing someone multiple times AND getting them to do an assignment is time consuming and takes away from a job they already in order to work from your company. The least you could do is get back to the candidate and say they weren't selected.