A few months ago, I did a post about my guess that someone whose first language is widely spoken would be less likely to speak English than someone whose first language is relatively obscure. It looks like I've been outdone.
English First has done a study that assesses the English proficiency of adults in various countries. From this, they have put together an English proficiency index and made some pretty nifty maps and plots.
The English First folks also investigated the same phenomenon that I did in my post. Clearly they have a much bigger budget (greater than $0) for doing these sorts of things, and they didn't just cull their data from Wikipedia, so I tend to go with what they say. Good thing their results support my own-- again, that people whose first language is shared by many are less likely to speak English. However, the relationship they found was "weak." See below.
If you're upset by the fact that the relationship here appears to be in the opposite direction of that which I found earlier, don't be. I was looking at the negative log of the number of native speakers. Why I transformed the data like that, I don't actually remember, but rest assured that this is showing roughly the same thing. Of course, this isn't exactly the same thing, the most obvious reason being that they are looking at "English proficiency", whereas I was looking at the "percent of English speakers."
They also compare English proficiency to various other variables they believe should be related, such as the value of exports per capita, the average number of years of schooling, and gross national income per capita. All of these had a stronger relationship to the English proficiency than the native speakers variable.
One last mildly interesting nugget of information, which was mentioned in the Brazilian article that pointed me to the English First study and website, is that all of the BRIC countries fall right in line. China, India, Brazil, and Russia took the 29th, 30th, 31st, and 32nd spots respectively. The article also pointed out that, although world wide Brazil did not do so well in this ranking, at least it beat Venezuela and Chile!