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.


A housing estate in South London has a playground only richer children can play in

Not this playground. Image: Getty.

A simple children’s playground has become the latest symbol of the disturbing rise of stigma in our housing sector. The Baylis Old School development in South London has shocked and angered in equal measure as it has emerged that a playground developed on the site, and originally intended for use by all residents, has been restricted to block social residents from accessing the communal play areas.

Our housing system is widely acknowledged to be broken and in a state of emergency, but what’s often missed from this analysis is how badly this affects children who are subject to the often brutal outcomes of a property market that doesn’t take them into account. This development has been designed in such a way as to literally segregate the children in social homes from the other children.

The Baylis Old School is just one development. But it is symbolic of a much deeper problem – and a harsh reality that segregation and stigma are being institutionalised in our housing system.

In January, Shelter published the findings of our independent commission into the future of social housing, the result of the biggest exercise of listening to social tenants in recent times. It found more than half of the social tenants we spoke to felt they are portrayed unfairly, and one in six feels looked down upon because they live in a social home. A social home can change a life just as much as a job or an education, and yet we have normalised the idea that it’s somehow second class.

And it’s not just in social homes that our broken property market has institutionalised stigma. As Shelter has highlighted, private landlords and private letting agents are frequently putting up “No DSS” signs on adverts for properties or otherwise refusing to rent to those receiving benefits. These are people who can afford the rent, have exemplary records as tenants and yet are told their money isn’t good enough simply because they are relying on benefits as part of their income.

A home is a fundamental need. It’s the platform from which everything else we achieve in life can happen. Without a safe home everything is uncertain. And yet the market we are relying on to provide these safe homes is one in which discrimination is the new normal.  

We cannot go on like this.

Those children living in social homes in the Bayliss Old School development just want to play in the playground outside their window. The fact they can’t should give us cause us to ask some pretty fundamental questions. Yes, greater wealth will probably always get people a better and nicer home. But do we want to be a society where that wealth segregates and separates, or do we want to build the spaces which bring people together? Do we want a housing market which treats those who need some help from the state as if they are second class? Do we want to go on like this?

Our country has rarely felt as divided as it does today, but it really doesn’t need to be this way. Social housing, if built in the right way, and properly invested in, can be a source of national pride and unity. It can help people put down roots and it can build strong communities.

The Shelter Commission on social housing laid out a route to a better future where these practices are ended and we invest in three million new social homes throughout our communities for all families who need them. Now is the time to seize that opportunity. For the many who need a safe home and for the children told a playground outside their window is not for them.  

Greg Beales is campaign director at the housing charity Shelter.