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“Intimidating equations”

Taking lessons from Goldacregate, I’ve removed all the rant and sarcasm from this post.

In this article in today’s Observer, we’re advised that this:

P^{A} = gU_{G} + min(k – g, (1 – g)(1 – r))

is an “intimidating” equation”. Only if we’re easily scared! It relates the profit gained from dynamically priced airline tickets to some variables. This equation really is a very straightforward it says:

“profit equals two things multiplied together plus the smallest of two other things”

Using a Greek letter (capital pi) with a superscript following is a bit of showmanship, P would have done perfectly well in this instance. You can read the paper from which it is drawn here. It is written in the style of a paper in pure mathematics, which might explain the intimidation of the journalists in question.

I wrote a little bit about maths a while back: maths is the language of much of the science I do, but its a convenient tool – it’s not an end in itself. The seed of “Goldacregate” was a query by a journalist as to how to read out an equation, the thing is that practitioners rarely speak equations out loud: they scribble them on the nearest available surface (often illegibly, and incorrectly) or fight endless battles with machines to get them into electronic documents. Furthermore there is a long and dishonourable history of public relations companies using essentially meaningless equations to promote products and services.

For non-users of equations they are simply a cloak, a cloud of chaff thrown up to hide the truth beneath. For users, they are a compact and exact way of writing down the truth.

The next time you see an equation, don’t be scared beneath it there is something simple which can be said.

**Unexpurgated version: **Ah, bless, the economists are playing at being scientists by using an equation and the journalists have got the vapours at the impossible complexity of it all. Nasty equation: please, don’t hurt me.

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Did at first think they might be talking about products of geometrical progressions when they started waving their pi around… I found them pretty intimidating in my Mods exam!

@newshoot – yes, introducing big pi seemed a bit unnecessary. Turns out it is all really basic stuff tho'

I'll be honest when I looked at that equation in this mornings Observer it was the visual equivalent of white noise or indeed this bit in the Simpsons:

@GentlemanAdmn – I'm trying to help you breakout from this sort of thinking! To be fair the equation is relatively meaningless to me since the only term they define is the profit.

This is an equation which could be entered in Excel or any other spreadsheet program. Perhaps if people felt license (UK: licence) to do whatever they wished with math (UK: maths), then they would get over being intimidated.

Perhaps the journalist could point to a web page where someone had set up entry boxes for profit, U, etc. and the reader could play with it. That's how we originally learned maths, and perhaps something we should try to get back to.

(@agileroxy on Twitter)

@monotreme – that's the way we'd approach an equation – I suspect for most people the idea of playing with numbers in excel is a bit fearful. Equations really are for the use of practioners. The presentational style of the economics paper is quite striking, they are really trying a bit too hard!

That's what I was trying to say, rather inarticulately.

What I meant is that the economists, or perhaps some IT person at the newspaper, could set up a web page that would be opaque to the reader except for perhaps a graphic showing the equation being used and the definitions of the variables.

There would be entry boxes for all variables, and then one could play with entering different values and see how the equation changes. A graphing tool would be an additional plus, especially for people like me that like to see the output as a graph.

That way for the maths-averse amongst us, all they would see is the entry boxes and they could play "airline exec" and try to maximize their profits using different variable values. If the equation were complex enough, one could even have some sort of contest ("high score: Monotreme!") so that people could try to maximize the score. This would be trivial for 1-5 variables, but rapidly non-trivial for larger numbers of variables.