David's Computer Stuff Journal: Restaurants, immigrants, and the popularity of various cuisines

Restaurants, immigrants, and the popularity of various cuisines

David N. Welton — Tue, 13 May 2008 07:34:00 -0700

A little off-topic exercise conducted in the "eye of the storm", when Ilenia and Helen were still in the hospital:

A post on Seth Robert's blog brings up the idea that many Chinese restaurants were opened as a way to go into business without competing with native male workers. The post made the rounds of several other online journals.

That was the push I needed to get up and go collect a few statistics of my own, regarding an idea I've been kicking around for a while. My theory is that the number of restaurants of a given type, divided by the number of immigrants from that country might be an interesting way of guaging the popularity of the cuisine in question.

In order to simplify things just a bit, I actually used data from Italy, for the following reasons:

Most immigration to Italy is pretty recent, so it's not necessary to account for the length of time different immigrant groups have been present, and the effects that may have had on the diffusion of a given cuisine.
Immigration statistics were readily available: http://demo.istat.it/str2006/index.html
Italian the language almost completely corresponds to Italy the country (outside of a chunk of Switzerland, San Marino, and the Vatican), something that makes things that much easier.
I speak Italian, so it was easy to find out all the information I needed

Unfortunately, finding out the number of restaurants of various types is far from an exact measurement, and since this is a quick fun project, I just went for Yahoo search (they deserve credit for keeping their search API open when Google's was closed) results on terms like "Ristorante Turco" (Turkish), "Ristorante Messicano" (Mexican), and so on. This was the most expedient means of gathering information quickly, but this approach does present a number of obvious problems, listed here in the hope that someone without diapers to change and a business to run might come up with some good answers:

Some hits likely come from people talking about a restaurant that happens to be in a country, like "ristorante americano". "Nel tipico ristorante americano, ...." or in other words, "In a typical American restaurant", rather than an American-style restaurant in Italy, which is what we were looking for in the first place. This is probably also true of countries close to Italy, where people go on vacation and thus have occasion to write about their experiences in a "ristorante tedesco" (German), rather than going to eat in a German restaurant in Italy. Perhaps the search query could be improved in an attempt to eliminate this sort of false positive.
Some restaurants probably are not known as, nor brand themselves with a country name, but instead utilize titles like "Middle Eastern", "Arab", "South American", "African", or others that do not correspond with any one country in particular. It would be possible to group countries together with other adjectives, and get statistics for these clusters as well.
Measuring hits is measuring what people are talking about, rather than simply restaurants that exist, so if restaurants from a certain country are more talked about than others, that would muddy the statistics a bit. However, it seems reasonable that people would mostly talk about restaurants in proportion to their popularity, and I don't see a particular reason why there would be more talk of Vietnamese restaurants, say, than Thai restaurants, compared to the actual numbers.

That said, for a quick project, this approach seemed to work out ok, and the results appear credible. Obviously, the results also reflect people discussing certain cuisines, rather than an actual number of restaurants, but since it does reflect interest, we'll use the number in any case.

Since the number of restaurants/interest in a type of restaurant was clearly not correlated directly with the number of immigrants, other factors must come into play. For instance, "ristorante giapponese" turns up 125,000 hits, but the stats say only 6873 Japanese nationals live in Italy. As above, hits don't mean actual restaurants, but clearly Japanese cuisine is not being popularized through immigration.

Here's my guess: these statistics show, to some degree, what people in the host country actually like to eat. Food that tastes good means more restaurants. Things that aren't that popular mean few restaurants, even if there are many immigrants. To pick on one country, there are many Philippino immigrants in Italy, but very few search hits - and anecdotally, I've never seen a Philippino restaurant in Italy either, whereas even smaller towns like Padova have Chinese, Mexican (well, it's called that, even if it's a shadow of the real thing), Japanese, various Arab and middle eastern restaurants, and even a few less common things like Eritrean. And I know that many native and foreign restaurants employ Philippino cooks.

Below is the chart I whipped up showing the number of Yahoo hits per immigrant. The Italian names shouldn't be too hard to figure out. A few tricky ones: Giordano-Jordanian, Giamaicano-Jamaican, Spagnolo-Spanish. If you're interested in numbers or source code, contact me.

"Restaurants, immigrants, and the popularity of various cuisines" by M.Pomme

Fri, 16 May 2008 00:11:24 -0700

Hello Dave,

OK send it along please :)

"Restaurants, immigrants, and the popularity of various cuisines" by Dave Welton

Wed, 14 May 2008 12:56:18 -0700

M, I'd be happy to give you the original spreadsheet if you want to fiddle with and improve on it. This was just a fun exercise for me, though, so I don't think I'm really likely to sink that much more effort into it.

BTW, the numbers in my chart are different from the raw yahoo hits. There are tons of hits for things like Ristorante Cinese, but that's also balanced out by a great deal of Chinese immigrants, for example.

"Restaurants, immigrants, and the popularity of various cuisines" by Seth Roberts

Tue, 13 May 2008 17:26:23 -0700

Thanks for the publicity. You might want to take logarithms before plotting your data. It might make it easier to see a pattern.

"Restaurants, immigrants, and the popularity of various cuisines" by M.Pomme

Tue, 13 May 2008 15:25:35 -0700

OK, maybe I was a little harsh...

It would be interesting to compare this graph with the graph you obtain with just the number of google hits (not "normalized" in any way by the immigration office data). Does it look very different ?

Alternatively could you try using the data to find a estimation of a relation between the popularity and the population:

e.g., if we assume that there is such a relation and that it looks like this:

of google hits (G) = K * (population (P))^n

We can find n by choosing it so that the plot of G/P^n against P is the closest to its linear regression, and K is the coefficient for the linear regression.

Then, just make a bar graph of G/(K*P^n). The food from the country which value is > 1 tastes inherently "better" than the average food, and the ones with values < 1 tastes inherently worse than average :D

He he thanks for this post, I had forgotten maths could be fun...

I hope the theory above is not far too ridiculous ;)

"Restaurants, immigrants, and the popularity of various cuisines" by Dave Welton

Tue, 13 May 2008 11:57:20 -0700

I don't think they're "meaningless" numbers. I think they're rough, imperfect numbers with some potential inaccuracies, but I think they do confirm what 1) I've seen around town in a place like Padova, 2) what people I know like. There are doubtless some outliers (Mongolo, probably also due to its other meaning in Italy), but still, I think there's some truth there.

"Restaurants, immigrants, and the popularity of various cuisines" by M.Pomme

Tue, 13 May 2008 09:54:21 -0700

Just a comment on this:

"However, it seems reasonable that people would mostly talk about restaurants in proportion to their popularity"

While it sounds reasonable to assume people talk more about restaurants which are more popular, it's quite a leap to assume that the correlation is linear.

My uninformed guess would be an exponential correlation (or at least polynomial: x^2, x^3, x^n...), because talk generates more talk (viral marketing and "buzz" rely on that)

Anyway I'm afraid all of this is just crazy talking on meaningless numbers - but i guess you know that already :p

Regards,