Any good programmer should have no problem producing a portfolio of items he/she has worked on. Not every developer will have a brilliantly fleshed-out portfolio and that's fine. Regarding developers, Lilly points out that, "past projects or coding are proprietary or embedded in a past corporation's system."
Look for CodeProject, StackOverflow profiles or open source contributions. "This is an especially beneficial additional piece for candidates to talk about during the interview and for hiring managers to check out, Lilly says, "Other side projects that they're working on can act as pieces for their portfolio as well."
You'd also be wise to eye any public social networking profiles they maintain. Do they maintain a professional Web presence? Have they spent time bashing their last company or boss? Candidates beware, Lilly says, "all candidates in any industry should expect employers to Google them."
Knowing what type of work people have done in the past and seeing how they conduct themselves on social networks will give you a better understanding of the candidate's strong and weak points and how they will conduct themselves in the work place.
3. Do an In-depth and Structured Phone Interview
This process is designed to weed out the unqualified candidates and demonstrates how the interviewee will react when faced with a real coding challenge. There are a couple common mistakes that you should avoid.
Don't let the interviewee drive the conversation. Guide the interview and ask questions that you feel will pull the developer out of their comfort zone. Watch out for single faceted developers or programmers who have spent their entire career focused on only one platform. That should throw a red flag to employers. Don't just ask questions about items on a candidates resume, because they are well-versed on these items and have answers planned accordingly. Instead, Lilly says, focus on these questions.
What is their favorite language to develop in.
Why do they like it?
What would they change if they could make it a better language?
What has been their most challenging project to work on?
What new technology are they looking forward to using on their upcoming project?
What changes in the industry will affect the future
If you were in charge in your last position, what would you change to make it a better role for you?