Back of the envelope demography.

A warning, this is pretty much a shaggy dog story.

A while ago I had an idle thought about migrant settlement patterns. If there was a slight tendency amongst Chinese Australians to settle in ways that reflected subnational cultures from China (I was prompted by the Sydney suburb of Ashfield which is distinctly Shanghainese, not just Chinese), would the same tendency be visible in Indian Australians. After all, India is also vast and linguistically diverse, but has a far shorter history of unified statehood. Were there Punjabi and Bengali districts to go with the Shanghainese or Cantonese districts? I asked some bemused shopkeepers who did not have this impression. I then asked someone who may have looked at this as a professional (having published work on Indian migrants to Australia), a Professor Supriya Singh at RMIT. She kindly replied to my query (and I quote in part)

We have asked the question also but found there is no predominantly Indian suburb, and no  Punjabi, Malyali, Gujerati or Andhra concentration.

In the media there has been comment that Point Cook is developing into a very Indian suburb, with every third house being Indian. But there is no hint that it is concentrated in any one region of India. However when you look at Census distribution maps, there are no areas of Indian concentration in the way that there are Chinese, Italian or Greek cultural precincts or clusters.

This was striking in another way. Not only no clustering of subnational groups, but no clustering at all. Not only did this seem unusual compared to other migrant groups, it also seemed unusual compared to Sydney. Afterall my subjective experience would cite suburbs like Parramatta and the adjacent Harris Park, as well as other places as having a distinct Indian presence – I’d go there to try subcontinental sweets – and they were used as natural sites for cultural events like Parramasala, or a A.R Rahman concert. Maybe there was a difference between the cities. So I knocked up some maps of people born in India recorded in the 2006 census.

I thought I could see a difference. Since I’m from neither city I’m not keen to indulge in the inane narcissism of small differences popular amongst the denizens of each – especially since I struggle to think of two cities that size that are so staggeringly alike (and of course I was looking at people chosen for the fact they weren’t born there). If there was a difference it was probably geographic. A tendency to cluster isn’t the desire to be away from people unlike you, just being able to have access to people with whom you have similarities or bonds or at least provide a critical mass for shared interests (including shops, leisure activities etc.).1 If a city is harder to get around because the topography is more rugged, and broken up with waterways (as is Sydney) then the  distance as the crow flies to those you want access to must be shorter compared to a city that is able to have very long straight streets through suburb after suburb like Melbourne. This means that networks amongst similar people will be more geographically concentrated and thus visible.

Of course, if it was true for Indians, it’d be true for other groups, both defined by ethnicity or by subculture or merely friendship. There isn’t a great source of data on most of these except ethnicity and religion though, and different ethnic groups coming at different times and in different circumstances faced different house prices and job opportunities. Relatively recent migrant streams such as Indians would find the places where post war migrants found cheap housing more expensive and the factories where they found work long gone. Unlike groups that were rooted in a refugee movement (such as 1970s Lebanese or Vietnamese) they wouldn’t have clusters created by state housing for early arrivals that would attract new members. So I decided to mock up some more maps for other relatively recent, non refugee groups, some of which I used in this post. I still thought that I could see a difference between the two cities.

Then I got worried that I was too invested in the hypothesis, and was seeing what I wanted to see. If I was going to see if it was really plausible I’d best see some numbers.

I thought about finding/creating an adjacency matrix for the Statistical Local Areas (SLAs) so I could do a regression without treating places that were right next to each other as being as independent as places on opposite sides of town, then I decided I was too lazy. I’d save the spatial econometrics for later, back of the envelope stuff was good enough for idle curiosity. Instead I just threw what was in my toolbox at the question. I’m an economist of some variety so when measuring how concentrated migrants were, the tools easily at hand where those measured concentration of income, and concentration of markets.

Here’s the Gini Coefficients for the distribution of several vaguely similar migrant groups and religions across post codes 2 in Sydney and Melbourne. In the very implausible scenario that every post code had the same number of people from cited group it would be 0. If they were all in single postcode it would be 100. The figure for all people in the city is given for comparison. Green difference figures indicate a less even distribution in Sydney.

Sydney Melbourne Difference
Philippines 68.7968684593 67.90822433 0.8886441293
Korea 72.455829353 70.65068982 1.805139533
India 68.8589406565 60.96744805 8.4253213365
Samoa 83.0240329007 82.30248531 0.7215475907
Assemblies of God 59.5215078447 60.43361932 -0.9121114753
Hindu 70.971124061 61.7110768 9.260047261
Jew 83.6440067426 87.53693137 -3.8929246274
Islam 75.8193284412 73.20723085 2.6120975912
Atheist 44.991356297 42.87549801 2.115858287
Buddhist 65.590195564 64.7922521 0.797943464
Everyone 39.43715859 42.87549801 -3.43833942


Which is interesting. The distribution of all people over postcodes was somewhat more even in Sydney, but less even for all but two groups (one of which was the AOG which is stereotypically confined to the Hills District). And the Indian born and Hindus (there is obviously considerable overlap) are where the discrepancy was most notable.

And here is Herfindahl Index, usually used to measure market concentration. Since there are less post codes in Melbourne the hypothetical even distribution would return a higher figure, but mildly so and is shown.

Sydney Melbourne Difference
Even distribution 0.0040322581 0.0043290043 -0.0019138962
Phillipines 0.0198548757 0.0161513385 0.0020863872
Korea 0.0198093499 0.016169897 0.0020223029
India 0.0213923313 0.0106830378 0.0090921435
Samoa 0.0434991191 0.0267859153 0.0150960538
Assemblies of God 0.0128796467 0.0108779384 0.0003845583
Hindu 0.0211560881 0.009934265 0.0096046731
Jew 0.0512464806 0.0460106973 0.0036186333
Islam 0.0251368972 0.0179790349 0.0055407123
Atheist 0.007183034 0.0049861153 0.0005797687
Buddhist 0.028045002 0.0131586278 0.0132692242
Everyone 0.00625315 0.004636 0.00161715

So that leaves me with a back of the envelope idea that the hypothesis is plausible enough to investigate further 3. But….why? There’s no important implications, except maybe that it might lead to differing segregation, which doesn’t seem likely based on degree of difference and people who have looked at it more carefully than I have little fear. It might have political implications if people cluster on political beliefs as is the thesis behind this, and it might interact and influence the class sorting dynamic that Antony Green sometimes talks about, which might be interesting and I have ideas on how to look at it, but there’s already enough political arithmetic out there.

So it’s a hypothesis that might prove to have some validity if more than a back of the envelope analysis was used, but there’s real reason to do so.

And I found myself wondering how an idle question and vague speculation allowed me to spend all this time seeing whether it was mildly plausible or just my imagination and cognitive biases, just to come with an answer of “maybe”. Shouldn’t I look at something important, something with policy implications (there’s a budget or something tonight), or at least something I get paid to do? Or better yet, why not go read a book/comic or spend time with loved ones or fly a kite.


But I’ll probably still keep doing things like this.


1 And ethnicity is just a highly visible trait, which is why we notice it, but I don’t know if it’s particularly special in this regard, apart from providing data which is why I mainly deal with it here.

2 A postcode was determined as being in metro Sydney or Melbourne by whether it you’d get next day delivery via Express post from that city.

3 I initially started typing out every single reason I could think of why this process was flawed, but it’d take up too much room and it wasn’t really the point.



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About Richard Tsukamasa Green

Richard Tsukamasa Green is an economist. Public employment means he can't post on policy much anymore. Also found at @RHTGreen on twitter.
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Incurious and Unread (aka Dave)
Incurious and Unread (aka Dave)
12 years ago

Do you need to quote your results to 10 decimal places?

12 years ago

I really don’t know anything like enough about Sydney to suggest some hypotheses as to why this is so, however I would suggest that racism and a sense of other is perhaps higher in Sydney (see Cronulla riots), do to enclaves of ethnicity.

Jews in melbourne have always (since the 19th century) been concentrated in St Kilda, Elsternwick and nearby. Just where the synagogues were built I guess.