Thursday, 29 July 2010


I have two things to say about queues today. The second one is inspired by Steven Landsburg, and I was reminded of it by the fact that I spent 40 minutes of today standing in a queue to get on the London Eye. Time which was essentially deadweight loss to the world.

The first is simpler, and I was inspired to write it by AJ Jacobs. AJ Jacobs is the author of The Year of Living Biblically, and I'm currently reading his new book "My Experimental Life". He's one of those journalists, who does crazy things and writes about them (he claims because he has nothing interesting in his past to write about - although why he can't just make stuff up like everyone else, I don't know). Anyway, the chapter of the book I was just reading is called The Rationality Project. Jacobs, having read Predictably Irrational and Nudge (but no doubt not having actually read Tversky and Kahneman) decides to rid himself of all of his irrational biases. He fails in funny ways, of course, and has a few interesting things to say along the way.

Anyway, at the end of the chapter he has a few points to make. Things he does differently since spending a month trying to be as rational as possible. Some of these are sensible: "I read menus from the bottom up" (because they are designed to be read from the top down - and are carefully designed to 'nudge' you into buying whatever the restaurant wants you to buy that day); "I spend a few minutes each week reading Michelle Malkin's conservative musings" (because he disagrees strongly with Michell Malkin, and only reading things by people you agree with is a sure way never to change your mind).

The one that I take issue with is this: "I make a note every time I'm in a fast moving grocery line". Now, the idea behind this is obvious:
We all are predisposed to notice and remember the bad stuff... when we're on a checkout line behind an eighty-two year old man paying with a sack of pennies and nickels.
But it's a really, really bad example to choose of this particular phenomenon because we actually do spend more time in slow-moving queues than in fast-moving queues. This is obvious once you think about it: slow-moving queues move slower! So if all queues were the same length, but with random speeds (which were impossible to predict before you join) you would still spend most of your time in slow-moving queues. You're just as likely to choose a fast queue, but every time you do choose a fast queue, you get to the front of it quicker.

If you want to avoid believing in the signficance of random events, you should make a note of every time you take your umbrella out and it does rain (or choose not to take it and it doesn't). You should remember every time you have a really strong feeling that you're about to get a phonecall from your grandmother and then you don't, or every time you meet someone who doesn't share your birthday.

I said I had two things to say about queues, but it's late, and I've spent longer than I expected writing about that one. I'll do the other one tomorrow.

Tuesday, 6 July 2010

Things I wish I'd read earlier: I Pencil

I'm going to start an occasional series in which I'll post links to several articles and books that I wish I'd read earlier (or if they're in copyright, links to somewhere you can buy them). Mostly because if you're reading this, and you haven't read them, you're probably going to enjoy them.

Also, I kind of plan to post something sometime about what I think they should teach in schools (and which parts of the current curriculum they could afford to miss out) and I think most of this belongs there.

I Pencil

I think by the time I finished school, I had just about heard of the Invisible Hand, but I'd never been taught about it, and didn't *really* understand what it meant. The genealogy of a pencil is an incredibly powerful illustration of what it means. I challenge anyone to read it and not be amazed by the power of the price system (why don't more people cite *that* as a proof of God's existence?). The fact that I can walk into a shop whenever I want a loaf of bread and be sure that I'll find one on a shelf really is a miracle - everyone should be reminded of that every now and then.

Monday, 5 July 2010

How not to draw a graph

The Daily Mail had an article earlier this year reporting some research which stated that people are happy at the age of 15, gradually drop off in satisfaction until the age of 45, then get happier again until a peak at 74. There are a few potential problems I can see with the research (asking people to self-report on their happiness has always seemed pretty dodgy, and have they properly controlled for some years just being less happy than others?) But that's not the issue here. The issue is the "graph" they used to illustrate the research.

Let's have a look at it:
Yes, really. That is a genuine graph directly from the website (in fact, that picture is being hosted on their website, I couldn't be bothered to download it). Look at the scale... The horizontal axis doesn't have one! The distance from 15-40 is the same as the distance from 40-50! Why would anyone make the graph look like that? Would they really be unable to make the same point using a graph with sensible axes?

Let's have a look:
That doesn't really look any less impressive (apart from the fact that I drew it in about 10 minutes in GIMP, and the Daily Mail hires qualified graphics people), and the patterns are still pretty clear. The slight upward trend in the 40's starts before 46 (but that's also true on the Mail's original) and the *massive* peak at 74 does start to look a bit suspicious... could it be a small-numbers effect?

Why did the Mail choose to go with the inumerate version? Apart from the obvious, I genuinely can't see how theirs is better than mine on any dimension, and it's pretty obvious in which ways it's worse.

HT to Dave in the comments at BishopBlog

Sunday, 4 July 2010

Non-news story of the week: Union demands higher pay for its members

The National Union of Teachers has complained that teaching assistants have been used instead of teachers to look after classes full of kids. This has resulted in job opportunities for supply teachers (who are members of the National Union of Teachers) dropping significantly.

I can barely imagine a purer example of what unions are really all about: cartels formed by workers to artificially drive up wages. Using teaching assistants to look after a classroom is not only a Bad Thing, it is also illegal (presumably thanks to the efforts of organisations like the NUT). Unless teaching assistants are capable of looking after a classroom full of kids, why would anyone bother with a law like that?

Unions tend to put themselves forward as defending some sort of moral principle (even when they're supporting laws which ban people from hiring low-skilled workers). It can hardly be a coincidence that their moral principles always happen to coincide with the interests of their members...

Saturday, 3 July 2010

'Minor Delays'

I have spent a long time wondering exactly what is meant by 'minor delays' on the Tube. They have a fixed amount of track, and a fixed number of trains running on it. The only way for their to be delays is for the trains to slow down... how is it possible that 'a customer incident' which happened over an hour ago is still causing the trains to run slower?

I can just about see why there are delays at peak times (the trains run slower because they spend longer in each station) but how do 'delays' propogate through the system? I can see how there might be bunching, but 'delays' (or is that what they mean by delays?)?

Thursday, 1 July 2010

Equal Prize Money at Wimbledon

People have been going on (again) about equal prize money at Wimbledon. Lots of people have been saying (again) that it is right that pize money is now equal. Lots of people have then been responding (again) by saying that this is silly because the men play 5 sets while the women play only 3.

No-one seems to have noticed (again) that the prize money for the junior section is even less than the prize money for the women... how can this be fair? They play the same number of sets!

And the prize money for the World Tiddlywinks Championship (spot the familiar face, for those at QM...) is even lower!

In fact, the prize money for the annual 'working at MacDonalds for 40 hours a week' championship would barely pay for Andy Murray's chicken baguettes, and yet no tennis player would dream of playing 40 hours in the entire two weeks of Wimbledon - how can this be fair? The '5 sets' crowd seem to adhere to some bizarrely warped form of the Labour Theory of Value (inasmuch as they have any principle at all) - why not insist on equal prize money for burger flippers?

Seriously, how can anyone possibly imagine that the prize money for a tennis tournament is proportionate to the amount of work put in, or that the prize money for two entirely different tennis tournaments should necessarily be the same?

I am not an economist, so I don't want to try to explain how the prize money *is* determined. All I know is that neither the "equal prize money" crowd nor the "but they play 5 sets" crowd has captured the full story.