Bob Martin’s idea
Bob Martin of Object Mentor posted an interesting variant to get around this problem: a base fee per story point, plus a lower-than-usual (close-to or below cost) fee per hour. This biases the contracted company’s to deliver early, but gives them some protection in case work proceeds slower than expected. Bob Martin described it this way:”[A]gree to pay a certain amount for each point completed, plus a certain amount for each hour worked. For example, let’s say you’ve got a project of 1000 points. Let’s also say that a team of four has established an estimated velocity of 50 points per week. This looks like about an 80 man-week job. At $100/hour this would be a $320,000 job. So lets reduce the hourly rate to $30/hour, and ask the customer for $224 per point. This sets up a very interesting dynamic. If the job really does take 80 man-weeks, then it will cost the same. If it takes 100 man-weeks then it will cost $344,000. If it takes 70 man-weeks it will cost $308,000. Notice that this is a small difference for a significant amount of time. Notice also that you, as developer feel strong motivation to be done early, since that increases your true hourly rate.” I have not seen that model in action myself, but several people have written in recommending it.
