A general theory of procrastination: U=E*V/(Gamma*D):

Steel combined hyperbolic discounting with a theory of motivation called expectancy theory, and came up with something he calls temporal motivational theory (TMT). It boils down to this:

Utility = E x V / Gamma D

Utility is the desirability of getting something done. E is expectancy, or confidence. V is the value of the job, and includes not only its importance but also its unpleasantness. Gamma stands for how prone a person is to delay doing things. And D means delay, or how far away the consequences of doing, or not doing, the task are.

The bigger the top number compared to the bottom, the less likely a task will be put off. So if you expect to do well at a job (E), and it's a pleasant thing to do (V), and you're not prone to being delayed by distractions (Gamma), and it has to be done right away (D), you're not likely to procrastinate.

If you expect to fail at a difficult task and you're easily distracted and it doesn't have to be done for quite awhile, you're going to procrastinate.

Upon retrospective introspection, the equation seems obvious (though I wonder if the linear and inverse linear proportionalities are less accurate than some other power law.)