Some key points to note on the criteria of selecting a candidate:
The coding assignment was a huge asset in determining people’s real abilities. Some of the nicest assignments came from those with academically weaker performances. You could clearly see who the hackers and potential future computer science professors were. Without the assignment, the selection process would have been much harder, so I’m glad that it was something we required the applicants to do.
On some key points to indicate a good programmer:
Open Source contributions
Social media involvement in the programming community. Did they have a StackOverflow profile? A Twitter account related to programming? Perhaps a a blog dedicated to the subject? While these points alone certainly don’t mean someone is a good programmer, they are a decent indicator that a person is at least passionate about the subject.
Knowledge of unusual programming languages. Again, this is no guarantee that someone is a good programmer, but chances are that they have an above average interest in our profession.