Comment »Posted on Tuesday 9 December 2008 at 5:50 pm by Jacob Aron
In Getting It Wrong, Mathematics, Psychology

Long term readers of Just A Theory may remember that one of the very first posts here was about a pet hate of mine: junk equations. Back then it was a formula for fame, but this time it’s the bane of students with essay deadlines ever: procrastination. Thankfully I handed in my essay yesterday, so I have some free time to rip in to this nonsense.

Professor Piers Steel has, according to the Telegraph spent “more than 10 years” studying why people procrastinate. Depending on who you ask, he’s either a psychologist or a business professor at the University of Calgary (the Telegraph say the former, the Daily Mail and the Times the latter).

On to the equation itself. It’s U = EV/ID, where U stands for “utlity”, or your desire to complete a given task. E is the expectation of succeeding in your task, whilst V is the value of completing it. I is the immediacy of the task, and finally D is your personal sensitivity to delay.

Well, that’s what the Telegraph says. The Daily Mail give a different formula: U = EVTC, where T is your tendency to delay work, and C the consequence of not completing it. By simple substitution, it must be that 1/ID = TC. Now, I can see an argument for saying that T has just been re-written as 1/D (in the same way that you can write 0.5 as 1/2), as they are both about delay, but how does the immediacy of the task (I) relate to the consequence of not completing it (C)? Already I’m starting to see the cracks in this equation…

For the definitive answer I went to Prof. Steel’s website, which provided me with the following:

Yet more variables! We’ve already met U, E, V and D, but now we have G (which seems to be standing in for the Greek letter Gamma which was actually used in the equation). Confusingly, G appears to be taking the place of D in the equation described by the Telegraph, whilst D here is now I. To avoid any further confusion, I will refer to Steel’s form of the equation, U = EV/GD from now on. To reiterate: E is expectancy of successful completion, V is the value of completion, G is the sensitivity to delay, and D is the immediacy of the task.

Besides changing variables like they were underpants, the problem with all of these formulas is that the values in them are completely unscientific and not at all measurable. Granted, your expectation of completing a task successfully could be expressed as a probability, for example, but such a measure is very subjective. What are the odds of getting an A for an essay? They simply can’t be calculated.

The other issue is the mathematical validity of the formula. If your sensitivity to delay is very low (and thus you have a small G), your utility value will be high – but surely it should be the other way around? If you don’t like to put things off, you’re less inclined to procrastinate! So maybe G should be measured from 1 to 10, with 1 being a high sensitivity and 10 being low. All this really illustrates is that it is very easy to come up with a formula for anything – as long as you fiddle the numbers to give that answer that you want!

Actually, it appears that this formula has more than one thing in common with the fame formula from my early post. Like that example, this equation is being used by its creator to publicise an upcoming book. Of course, all of the newspapers that have picked up this story are giving him a nice little bump of free advertising.

It shouldn’t need saying again, but I’m going to any way: these formula stories are a complete waste of time. They’re the absolute dregs of scientific journalism, and you shouldn’t pay any attention to them whatsoever. So, stop reading this and get back to work!


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