Posts filed under General (3156)

Team Ratings for Week 1

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the Rugby World Cup.

Predictions for Week 1

Here are the predictions for Week 1. The prediction is my estimated expected points difference with a positive margin being a win to the first-named team, and a negative margin a win to the second-named team.

Team Ratings for Finals Week 2

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 196 matches played, 115 of which were correctly predicted, a success rate of 58.7%.
Here are the predictions for last week’s games.

Predictions for Finals Week 2

Here are the predictions for Finals Week 2. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Round 6

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 38 matches played, 27 of which were correctly predicted, a success rate of 71.1%.
Here are the predictions for last week’s games.

Predictions for Round 6

Here are the predictions for Round 6. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Round 7

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 24 matches played, 16 of which were correctly predicted, a success rate of 66.7%.

Here are the predictions for last week’s games.

Predictions for Round 7

Here are the predictions for Round 7. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

(because I was asked about Keri Henare’s post)

Short answer: No.

As you know, we have four candidate flags. Two of them, the Lockwood ferns, have the same design with some colour differences. Is this a problem, and is it particularly a problem with Single Transferable Vote (STV) voting?

In the referendum, we will be asked to rank the four flags. The first preferences will be counted. If one flag has a majority, it will win. If not, the flag with fewest first preferences will be eliminated, and its votes allocated to their second-choice flags. And so on. Graeme Edgeler’s Q&A on the method covers the most common confusions. In particular, STV has the nice property that (unless you have really detailed information about everyone else’s voting plans) your best strategy is to rank the flags according to your true preferences.

That’s not today’s issue. Today’s issue is about the interaction between STV and having two very similar candidates.  For simplicity, let’s consider the extreme case where everyone ranks the two Lockwood ferns together (whether 1 and 2, 2 and 3, or 3 and 4). Also for simplicity, I’ll assume there is a clear preference ranking — that is, given any set of flags there is one that would be preferred over each of the others in two-way votes.  That’s to avoid various interesting pathologies of voting systems that aren’t relevant to the discussion. Finally, if we’re asking if the current situation is bad, we need to remember that the question is always “Compared to what?”

One comparison is to using just one of the Lockwood flags. If we assume either that there’s one of them that’s clearly more popular, or that no-one really cares about the difference, then this gives the same result as using both the Lockwood flags.

Given that the legislation calls for four flags this isn’t really a viable alternative. Instead, we could replace one of the Lockwood flags with, say, Red Peak.  Red Peak would then win if a majority preferred it over the remaining Lockwood flag and over each of the other two candidates.  That’s the same result that we’d get adding a fifth flag, except that adding a fifth flag takes a law change and so isn’t feasible.

Or, we could ask how the current situation compares to another voting system. With first-past-the-post, having two very similar candidates is a really terrible idea — they tend to split the vote. With approval voting (tick yes/no for each flag) it’s like STV; there isn’t much impact of adding or subtracting a very similar candidate.

If it were really  true that everyone was pretty much indifferent between the Lockwood flags or that one of them was obviously more popular, it would have been better to just take one of them and have a different fourth flag. That’s not an STV bug; that’s an STV feature; it’s relatively robust to vote-splitting.

It isn’t literally true that people don’t distinguish between the Lockwood flags. Some people definitely want to have black on the flag and others definitely don’t.  Whether it would be better to have one Lockwood flag and Red Peak depends on whether there are more Red Peak supporters than people who feel strongly about the difference between the two ferns.  We’d need data.

What this argument does suggest is that if one of the flags were to be replaced on the ballot, trying to guess which one was least popular need not be the right strategy.

Team Ratings for Finals Week 1

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 192 matches played, 112 of which were correctly predicted, a success rate of 58.3%.
Here are the predictions for last week’s games.

Predictions for Finals Week 1

Here are the predictions for Finals Week 1. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Round 5

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 30 matches played, 20 of which were correctly predicted, a success rate of 66.7%.
Here are the predictions for last week’s games.

Predictions for Round 5

Here are the predictions for Round 5. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Team Ratings for Round 6

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 20 matches played, 15 of which were correctly predicted, a success rate of 75%.
Here are the predictions for last week’s games.

Predictions for Round 6

Here are the predictions for Round 6. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

I usually don’t bother commenting on unsourced ‘nutrition’ claims, but the Herald has this one on the front page of the website, only four stories down from the increase in the number of Syrian refugees

It’s from the Daily Mail  and it’s about sex. That’s never a good sign.

Some of the advice is plausible — they say the same things about alcohol that the Porter does in Macbeth, though less felicitously phrased. At the other extreme

The trans-fats found in most fried foods are known to decrease the libido in both men and women by increasing abnormal sperm production (lower sperm count and slower sperm movement) in men and interfering with gestation in women.

That’s fertility, not libido. The difference is kind of important.

Chocolate is always a favourite of this sort of story

A known aphrodisiac, chocolate is absolutely delightful, as it is full of anandamide and phenylethylamine, two ingredients that cause the body to release the happy hormones, known as endorphins. However, while the happy hormones are great, cocoa also contains methylxantines, which can make us lethargic and lower the libido.

The concentrations of anandamide and phenylethylamine have been demonstrated to be too small to have an effect.  Also, anandamide doesn’t release endorphins — it has a direct effect (in larger doses) as a cannabis analogue. And phenylethylamine doesn’t release endorphins; it has direct but different drug-like effects (again, in larger doses).  Methylxanthines are actually present in chocolate at what might be biologically relevant levels, but that description of their effects is very unusual: the best known one is caffeine.

There’s also the common sort of  translation problem with stories from the other side of the world.  Red meat in New Zealand typically doesn’t contain hormones used to promote animal growth — it’s illegal for lamb or venison and rare for beef. [Update: actually, this part wouldn’t be true in the UK either]

Overall, the food effects are either untrue or exaggerated, which is pretty much what you’d expect given the topic and the source.  If your favourite member of the appropriate sex likes chocolate, giving them some might or might not have the desired effect. If it doesn’t, the problem probably isn’t the methylxanthines.

Team Ratings for Round 26

The basic method is described on my Department home page.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Performance So Far

So far there have been 184 matches played, 106 of which were correctly predicted, a success rate of 57.6%.
Here are the predictions for last week’s games.

Predictions for Round 26

Here are the predictions for Round 26. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.