We used big data to divide city-dwellers into six “tribes”

A generic picture of New York City. Image: Getty.

Whether tapping a contactless card to take the subway, buying a gift for a loved one or using a smart phone to find the way home, your everyday actions leave behind breadcrumbs of digital information. When these traces are collected and analysed en masse, they can help urban planners to pick up on the daily rhythms of the life of a city and uncover trends about the people who live there.

In a recent study, we developed a new mathematical framework which extracts various spending habits or lifestyles from the digital traces left by credit cards and mobile phone data in Mexico City. We discovered that purchase habits not only related to socio-demographic characteristics such as age, gender, income and mobility – they also related to the places people visit, and the people they call.

Over the past decade, smart phone data has helped researchers to understand and plan cities. For example, location data is used in transport planning to identify which stations and routes are busiest at different times of the day. For example, scientists have found that people don’t necessarily take the optimal route to their destination – instead, they have a favourite route for trips they perform routinely, and a few alternative routes which they take less frequently.

Meanwhile, credit card data and spending behaviour data have been used from the retail companies to build a profile of consumers, based on their set of purchases. This is illustrated by the parable of the beer and nappies. As it turns out, on Friday evenings, young men who buy nappies also have a predisposition to buy beer – this group became parents.

When analysed across the years, these digital traces can help scientists and governments to understand at an unprecedented scale how societies in different parts of the world cope with major events, such as recessions or major policy changes.

The six tribes

From the detected spending habits, we identify six groups or “tribes” while protecting people’s privacy by aggregating the data and ensuring they were anonymous. Each of these groups has a core purchase, which is the most frequent of their spending activities, indicated by the yellow arrows in the figure below.

Our six lifestyle groups: the colour of the arrows represents the frequency of the transactions, from yellow (most frequent) to red (less frequent). Image: Riccardo Di Clemente et al./author provided.

The “commuters” tribe is mainly made up of adult men who live far from the city centre. They commute by car (paying tolls), earn above average incomes and enjoy eating at restaurants.

Middle-aged women dominate the “household” tribe and tend to have the least expenditure and mobility. Their core transaction is grocery shopping, they have lower incomes and live in the suburbs. On average, members of this group receive more phone calls from the other tribes.

Young people are split between two tribes. The “young”, who are under 30 years old, live in the city centre, mainly use taxis as means of transportation and have an average income.

The second group, called “high tech”, is slightly older, with an average age of 35. Their core transactions are on technology such as smart phones and computers. They could be young professionals, since they have higher than average expenditure, a wide range of contacts in their mobile phones and do most of their activities downtown.

The “dinner out” group lives closer to the city centre. Their core transactions are restaurants. They also have more contacts in their social network than average.

We also created an “average” group from a random sample of citizens, to use as a benchmark, against which we could compare the spending habits and socio-demographic information of the other tribes.


Helping urban challenges

By generating useful information from these digital traces, we hope to help cities to embrace the digital revolution and resolve important urban issues, such as how to make cities more inclusive.

For example, the commuters tribe may be hit hardest by fuel price increases which may affect their spending and commuting. The creation of inexpensive and efficient public transport systems may be an important investment in urban areas, especially those where low-income residential areas and job opportunities are not in proximity. And to help the household tribe, we could consider introducing nutrition subsidies – programmes to incentivise low-cost grocery stores in areas where it’s difficult to find affordable, good quality food.

What’s more, our study shows that it is possible to gather information about daily mobility, social contacts and lifestyles by collecting the data that people already produce, rather than undertaking surveys which are expensive, time consuming and very limited in sample size.

This kind of analysis can help city authorities make informed decisions based on data about an unprecedented number of people and lead to more tailored policy to the specific needs of different groups and lifestyles.

The Conversation

Riccardo Di Clemente, Newton International Fellow of Royal Society, UCL and Marta Gonzalez, Associate Professor of City and Regional Planning, University of California, Berkeley.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 
 
 
 

The Fire Brigades Union’s statement on Theresa May’s resignation is completely damning

Grenfell Tower. Image: Getty.

Just after 10 this morning, Theresa May announced that she would resign as Britain’s prime minister on 7 June. A mere half an hour later, a statement from Royal Institute of British Architects president Ben Derbyshire arrived in my inbox with a ping:

“The news that Theresa May will step down as Prime Minister leaves the country in limbo while the clock ticks down to the latest deadline of 31 October. While much is uncertain, one thing remains clear – a no deal is no option for architecture or the wider construction sector. Whoever becomes the next Prime Minister must focus on taking the country forward with policies beyond Brexit that tackle the major challenges facing the country such as the housing crisis and climate change emergency.”

I was a bit baffled by this – why would the architecture profession try to get its thoughts into a political story? But then Merlin Fulcher of Architects Journal put me right:

Well you know construction is a larger contributor to GDP than financial services, and most of the work UK architects do is for export, and at least half of the largest practice (Foster + Partners) are EU, so there's a lot at stake

— Merlin Fulcher (@merlinfulcher) May 24, 2019

So, the thoughts of the RIBA president are an entirely legitimate thing to send to any construction sector-adjacent journalists who might be writing about today’s big news, and frankly I felt a little silly.

Someone else who should be feeling more than a little silly, though, is Theresa May herself. When listing her government’s achievements, such as they were, she included, setting up “the independent public inquiry into the tragedy at Grenfell Tower” – a fire in a West London public housing block in June 2017 – “to search for the truth, so nothing like it can ever happen again, and so the people who lost their lives that night are never forgotten”.

Matt Wrack, general secretary of the Fire Brigades Union, is having precisely none of this. Here’s his statement:

“Many of the underlying issues at Grenfell were due to unsafe conditions that had been allowed to fester under Tory governments and a council for which Theresa May bears ultimate responsibility. The inquiry she launched has kicked scrutiny of corporate and government interests into the long-grass, denying families and survivors justice, while allowing business as usual to continue for the wealthy. For the outgoing Prime Minister to suggest that her awful response to Grenfell is a proud part of her legacy is, frankly, disgraceful.”

A total of 72 people died in the Grenfell fire. At time of writing, nobody has been prosecuted.

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

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