In an earlier post I mentioned how I would like to find a conversation algorithm, and how I owned a book that showed the mathematics of marriage in dynamic non-linear models. Wait sec. I didn't mention that. I had originally mentioned it, but deleted that bit. Anyway, just a few minutes after I wrote that post I found this article where Dr. Piers Steel represents procrastination in a mathematical formula.
It seems the desirability of a task is directly proportional to the expectancy of succeeding in that task and the value of completing that task, and inversely proportional to the immediacy or availability of that task and one's sensitivity to delay.