The article raised some questions about how much time to spend for free on the interview process and also on free work whether at the whiteboard or "homework" for an interview process.

Here are my thoughts and experience and rules of thumb.

A rigorous interview process is something like:

1. send resume or CV

2. half hour phone or sometimes video screening interview

3. one hour in person screening interview (optional)

4. all day interview or equivalent with at least three different people including the hiring manager (unless there are fewer than three people at the company). This usually includes free lunch with the hiring manager and/or his team.

5. company checks references after the interview

A really rigorous interview is about 6-8 hours of the candidate's time, generally without compensation except for travel and often free lunch during the day.

In most cases, a lengthy interview process like this means about a 1 in 2 or at worst 1 in 3 chance of getting an actual job offer.

My general rules are:

Avoid phone screening interviews longer than 30 minutes unless the employer is out of the area. I once had a lot of 60 minute phone screening interviews that went nowhere. My feeling is if the employer is serious about you and in your area, they can and should meet you in person for a longer screening interview. Longer being over 30 minutes. Despite the many limitations of interviewing, it is easier and more reliable to evaluate each other in person than on the phone or even by video conferencing.

It is reasonable for a potential employer to have a longer screening interview if they are going to pay to fly you to an interview, provide a hotel, etc. Prefer a video screening interview to audio only if you can get a good video connection. Prefer the phone if the video connection is poor.

The potential employer should at least pay for travel including air faire, rental cars, hotels, any public transit. If they won't pay, they aren't serious and you should not pay for the trip either. A per diem or reimbursement to cover meals is nice, but not everybody does this and I would not turn down an interview if everything else was covered.

If they want more than at most eight (8) hours of free work whether whiteboard or "homework" to evaluate you, they should pay for your time. It should be a "try and buy" consulting project for them to get to know you and for you to get to know them. It is not just technical competence, but how well do the two of you work together; that is generally a bigger concern than technical competence.

Actually, I would be very cautious about more than three (3) hours of free "homework" or actual coding (not whiteboard) that they could directly use. If they are serious, they can pay a reasonable hourly consulting rate (e.g. $50-$100/hour) to try you out and vice versa. That is not that different from the cost of the time to interview you in person or cover travel expenses. If they won't pay, they probably aren't that serious and may simply be conning you to get free work.

In general, avoid doing work for free unless you get something else of lasting value to you from the free work such as something for your portfolio, lasting credit and recognition, or valuable experience you cannot get otherwise. Cash is king.