Strictly Voting Systems

One striking thing about the successive controversies over Strictly Come Dancing is the apparent lack of attention to detail paid to the technicalities.

When it first occurred to me that John Sergeant was likely to win the competition, I spent a while trying to work out whether the judges would be able to get rid of him somehow. I was handicapped by not knowing what the scoring system was, or how many couples were supposed to get to the final.

A day or two later he announced he was quitting, and, after kicking myself for not seeing that coming, I immediately wondered how they were going to handle being one couple short in the last few rounds.

Neither of the two questions I spent time pondering seemed to occur to the show’s organizers. They’ve now got round to explaining in detail how the scoring works. Even there there are oversights; I think it is an error to give both couples in a tie the higher number of points, although it doesn’t matter this late in the competition. Last week’s judge points should have been 2.5, 2.5, 1, rather than 3,3,1. That could have made a difference earlier in the competition.

However, I would take a more drastic approach. Collapsing the judges’ votes into an ordering of the contestants is throwing away information to begin with. It might be better to keep the actual points awarded by the judges, and then add the popular votes, scaled down to the same maximum. For instance, if there were a million votes, each judge point would be worth 1000000/160 phone votes. (about 6000). Apart from making the actual number of votes more important, that would encourage the judges not to bunch their votes into the 8-10 range all the time.

These type of shows have been going for years and years; I still think the problems appearing now are all because previously they never took the voting seriously, and would just cheat if they didn’t like the way it was going. Having people like Undercover Economist Tim Harford discussing it now is a real step forward. Maybe next year’s competitions will be designed by people who’ve heard of Arrow’s Theorem.


20:05 – phone voting is currently going on to select the last two.

Scores carried from last week are

Rachel 5 (3 judges + 2 phone)
Tom 4 (1 judges + 3 phone)
Lisa 4 (3 judges + 1 phone)

Tom ranks above Lisa because in a tie phone votes are worth more than judge votes.

The points from the judges this evening were

Lisa 3 (80)
Rachel 2 (79)
Tom 1 (73 or thereabouts, I can’t remember)

So the running total is:

Rachel 7 (3+2 judges, 2 phone)
Lisa 7 (3+3 judges, 1 phone)
Tom 5 (1+1 judges, 3 phone)

So Tom needs to win the popular vote to make it to the last 2, while the girls each just need to come second to make it.

Again, the compression of the judges’ votes has been very evident – no vote lower than an 8, no vote from 3 of the 4 judges lower than a 9. Len and Arlene, I think, each gave 9 to Tom’s first dance and 10 to the other 5 dances. What’s the point of being there if they can’t say which dance is better?

Tierney on Holdren

John Tierney attacks Obama’s science advisor John Holdren.

Dr. Holdren is certainly entitled to his views, but what concerns me is his tendency to conflate the science of climate change with prescriptions to cut greenhouse emissions. Even if most climate scientists agree on the anthropogenic causes of global warming, that doesn’t imply that the best way to deal with the problem is through drastic cuts in greenhouse emissions.

There is some merit on Tierney’s criticism, but it is obviously the reverse of what’s really happening. Whenever I have talked to a scientifically literate person who accepts the AGW consensus, and I have challenged it, it is never more than a couple of minutes before they something like “well, maybe there is room for doubt, but the things we should do about global warming are all things we should be doing anyway, like reducing fossil fuel use”.

It’s fair enough to believe both of those things, but each proposition needs to stand on its own without support from the other. Both sides of the debate have a tendency to shift ground when presented with strong arguments – do point me back here if you catch me doing it.

What matters about oil

Wonderfully deluded slashdot piece on using coffee grounds as a biofuel.

This is a great example of the misapprehension many people have about fossil fuels.

There are two vital facts about fossil fuels:

1. They burn
2. They are very, very, very cheap.

It’s the cheapness that makes them hard to replace – there are plenty of other things we could use, but none that are as easy to obtain as drilling a hole and pumping stuff out. One commenter pointed out that the year’s supply of coffee grounds would replace less than 3 hours of the USA’s gasoline consumption, but the real point is that the insignificance of a few pounds of stuff that still has to be refined or processed in some way should have been completely obvious to everyone.

Management costs again

Good post from Neil Craig on the cost of Crossrail. It reinforces the point I made last month, that for big or difficult projects, management is the biggest cost. In the private sector there is some pressure to economize on management, though not nearly as much as there should be because the decisions are all made by managers. With public sector funding (and the public-private fairy dust is of zero or negative benefit), there is no pressure.