Here's how you can use social media to spot early signs of gentrification

London's rapidly gentrifying East End. Image: Getty.

When you walk through a neighbourhood undergoing gentrification, you can sense it. The area is dominated by strange contradictions. Public spaces are populated by vagabonds and cool kids; abandoned buildings sit in disrepair next to trendy coffee shops; blocks of council housing abut glassy new developments.

Urbanists describe gentrification as a form of urban migration, where a more affluent population displaces the original, lower-income population. In statistics, gentrification appears as the lowering of crime rates, rising housing prices and changes to the mix of people who live there.

If we could only predict where gentrification is likely to strike next, we might be able to alleviate its negative impacts – such as displacement – and take advantage of its more positive effects, which include economic growth.

That’s why our latest study – conducted with colleagues at the University of Birmingham, Queen Mary University of London, and University College London – aimed to quantify the process of gentrification, and discover the warning signs.

Detecting urban diversity

We constructed four measures of urban social diversity using data from social media. By combining these measures with government statistics about deprivation, we were able to pinpoint a number of neighbourhoods undergoing gentrification in London.

Of course, social media is notoriously unsuitable for population studies, because of the “digital divide” – the split between people who can access the internet and those who can’t exists even within urban areas. And so, information from social media only captures part of the overall picture. Twitter users in particular are known to be predominantly young, affluent and living in urban areas.

But these are precisely the demographics responsible for gentrification. So, we used information from social media from 2010 and 2011 to define the “social diversity” of urban venues such as restaurants, bars, schools and parks.

Urban social diversity – in terms of population, economy and architecture – is known to be a factor in successful communities. In her famous book The Death and Life of Great American Cities, urban activist Jane Jacobs wrote that “cities differ from towns and suburbs in basic ways, and one of these is that cities are, by definition, full of strangers”.

Dropping in. Image: David Abrahamovitch/Flickr/creative commons.

In our work, we first measured the amount of strangers that a place brings together as the fraction of the social network of visitors who are connected on social media. This gave us an idea of whether a place tends to be frequented by strangers or friends. We further explored the diversity of these visitors in terms of their mobility preferences and spontaneity in choice of venues. Although we did not consider demographics or income levels, there is a known relationship between the wealth of people and the diversity of their geographical interactions.

We studied the social network of 37,000 London users of Twitter, and combined it with what we knew about their mobility patterns from geo-located Foursquare check-ins posted to their public profiles.

By studying the amount of strangers versus friends meeting at a bar, or the number of diverse versus similar individuals visiting an art gallery, we were able to quantify the overall diversity of London neighbourhoods, in terms of their visitors.

Networks are powerful representations of the relationships between people and places. Not only can we draw links between people where a relationship – such as friendship – exists between them; we can also draw connections between two places if a visitor has been to both. We can even connect the two networks, by drawing links between people in the social network who have visited specific spots in the place network.

In this way, we are able to extract the social network of a place, and the place network of a person. By the time we’d finished crunching the data, we could take stock of the range of people who had visited a specific place, and the different places visited by any individual.

When we compared the diversity of urban neighbourhoods with official government statistics on deprivation, we found that some highly deprived areas were also extremely socially diverse. In other words, there were lots of diverse social media users visiting some of London’s poorest neighbourhoods.


Diminishing deprivation

To find out what was going on, we took the newly published deprivation indices for 2015 and looked for changes in the levels of deprivation from our study period in 2011. The relationship was striking. The areas where we saw high levels of social diversity and extreme deprivation in 2011 were exactly the same areas that had experienced the greatest decreases in deprivation by 2016.

A prime example can be found in the London borough of Hackney. Anyone visiting Hackney might describe it in terms of the contradictions we mentioned before – but few of us could afford to live there today. In our study, Hackney was the highest ranking in deprivation and the highest ranking in social diversity in 2011. Between then and now, it has gone from the being the second most deprived neighbourhood in the country, to the 11th.

So, although social media may not be representative of the entire population, it can offer the key to measuring and understanding the processes of gentrification. Neither entirely good nor thoroughly bad, gentrification is a phenomenon that we should all watch out for. It will undoubtedly help to define how our cities transform in years to come.The Conversation

Desislava Hristova is a PhD candidate at the University of Cambridge.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

“Stop worrying about hairdressers”: The UK government has misdiagnosed its productivity problem

We’re going as fast as we can, here. Image: Getty.

Gonna level with you here, I have mixed feelings about this one. On the one hand, I’m a huge fan of schadenfreude, so learning that it the government has messed up in a previously unsuspected way gives me this sort of warm glow inside. On the other hand, the way it’s been screwing up is probably making the country poorer, and exacerbating the north south divide. So, mixed reviews really.

Here’s the story. This week the Centre for Cities (CfC) published a major report on Britain’s productivity problem. For the last 200 years, ever since the industrial revolution, this country has got steadily richer. Since the financial crash, though, that seems to have stopped.

The standard narrative on this has it that the problem lies in the ‘long tail’ of unproductive businesses – that is, those that produce less value per hour. Get those guys humming, the thinking goes, and the productivity problem is sorted.

But the CfC’s new report says that this is exactly wrong. The wrong tail: Why Britain’s ‘long tail’ is not the cause of its productivity problems (excellent pun, there) delves into the data on productivity in different types of businesses and different cities, to demonstrate two big points.

The first is that the long tail is the wrong place to look for productivity gains. Many low productivity businesses are low productivity for a reason:

The ability of manufacturing to automate certain processes, or the development of ever more sophisticated computer software in information and communications have greatly increased the output that a worker produces in these industries. But while a fitness instructor may use a smartphone today in place of a ghetto blaster in 1990, he or she can still only instruct one class at a time. And a waiter or waitress can only serve so many tables. Of course, improvements such as the introduction of handheld electronic devices allow orders to be sent to the kitchen more efficiently, will bring benefits, but this improvements won’t radically increase the output of the waiter.

I’d add to that: there is only so fast that people want to eat. There’s a physical limit on the number of diners any restaurant can actually feed.

At any rate, the result of this is that it’s stupid to expect local service businesses to make step changes in productivity. If we actually want to improve productivity we should focus on those which are exporting services to a bigger market.  There are fewer of these, but the potential gains are much bigger. Here’s a chart:

The y-axis reflects number of businesses at different productivities, shown on the x-axis. So bigger numbers on the left are bad; bigger numbers on the right are good. 

The question of which exporting businesses are struggling to expand productivity is what leads to the report’s second insight:

Specifically it is the underperformance of exporting businesses in cities outside of the Greater South East that causes not only divergences across the country in wages and standards of living, but also hampers national productivity. These cities in particular should be of greatest concern to policy makers attempting to improve UK productivity overall.

In other words, it turned out, again, to the north-south divide that did it. I’m shocked. Are you shocked? This is my shocked face.

The best way to demonstrate this shocking insight is with some more graphs. This first one shows the distribution of productivity in local services business in four different types of place: cities in the south east (GSE) in light green, cities in the rest of the country (RoGB) in dark green, non-urban areas in the south east in purple, non-urban areas everywhere else in turquoise.

The four lines are fairly consistent. The light green, representing south eastern cities has a lower peak on the left, meaning slightly fewer low productivity businesses, but is slightly higher on the right, meaning slightly more high productivity businesses. In other words, local services businesses in the south eastern cities are more productive than those elsewhere – but the gap is pretty narrow. 

Now check out the same graph for exporting businesses:

The differences are much more pronounced. Areas outside those south eastern cities have many more lower productivity businesses (the peaks on the left) and significantly fewer high productivity ones (the lower numbers on the right).

In fact, outside the south east, cities are actually less productive than non-urban areas. This is really not what you’d expect to see, and no a good sign for the health of the economy:

The report also uses a few specific examples to illustrate this point. Compare Reading, one of Britain’s richest medium sized cities, with Hull, one of its poorest:

Or, looking to bigger cities, here’s Bristol and Sheffield:

In both cases, the poorer northern cities are clearly lacking in high-value exporting businesses. This is a problem because these don’t just provide well-paying jobs now: they’re also the ones that have the potential to make productivity gains that can lead to even better jobs. The report concludes:

This is a major cause for concern for the national economy – the underperformance of these cities goes a long way to explain both why the rest of Britain lags behind the Greater South East and why it performs poorly on a

European level. To illustrate the impact, if all cities were as productive as those in the Greater South East, the British economy would be 15 per cent more productive and £225bn larger. This is equivalent to Britain being home to four extra city economies the size of Birmingham.

In other words, the lesson here is: stop worrying about the productivity of hairdressers. Start worrying about the productivity of Hull.


You can read the Centre for Cities’ full report here.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites

Want more of this stuff? Follow CityMetric on Twitter or Facebook