Not OP, but we do home work assignment instead of white board coding as well. While I can't be absolutely sure that they've done it themselves, a big part of t

Not OP, but we do home work assignment instead of white board coding as well. While I can't be absolutely sure that they've done it themselves, a big part of the in person interview is based on the homework, asking them how they would extend it, add specific features, potential performance problems they see, etc. Those answers are hard to fake if you didn't do it yourself We had one case where a candidate used some open source code snippets in his solution, not declaring and removing the comments and license headers. Still it was very obvious in the difference of coding style.