Background Image for Census 2021 - A big day for data


Census 2021 - A big day for data

With census day soon approaching on Sunday the 21st of March, we thought we'd get Blair's take on this once in a decade event.

19th March 2021

To watch the interview please click here.

What is the purpose of the census?

The purpose wow, so censuses have been around for thousands of years, they are a function of modern society, every industrialized society needs one, they obviously date way back, they exist in the bible - we know that's why Jesus was in Nazareth - and so they are a means of the state enumerating itself, of working out what it is, how many people there are, how much taxes to collect, where to spend money, so every modern society has to have them. We have to know where to spend money, where people are, are we growing, are we shrinking whatever we do so they are a fundamental part of our civil society; everyone has to have censuses.

Why is the census important and why should everyone fill it in on Sunday?

Yes, so first of all everyone fill it in you definitely have to do it, it's the law, it's not only a civic duty you can go to jail if you don't fill your census form in. So hang on, why is it important? Everything to do with how we allocate resources needs facts. I think in coronavirus [times], you know when people talk about data not dates, that comes back to the fundamental importance of data, of knowing things definitively and that is what the census gives us. So you think as you go about your daily lives - we use public transport, we need to go to hospitals, we use doctor's surgeries, we go to shops, we go to bars - all of these things fundamentally depend on where people are, on where people live, where people work, how they travel and the people who plan these things have to have fundamentally correct data and that is the one thing the census gives us. Everything else - surveys, mobile phone data, whatever - it is not definitive. The only time we get definitive truth is from a census, which is why for anyone in planning, whatever you plan you have to have the census data.

Why are you excited about the census 2021?

Well, first of all anyone who is interested in data should be excited. If the idea of the census and the new census data coming out doesn't excite you and you're in the data industry, you're probably in the wrong job. It should excite you, it's the once in every 10 years where we actually get this fantastically rich data resource and everything else that we do hangs off it, so there's all sorts of interesting things and every census brings new and interesting things. In 2011, we had an awful lot of new questions on ethnicity and nationality and identity, so that was fascinating to see. And also seeing change. Every census throws up, in stark relief, how our society has evolved. In 2011 we saw a dramatic drop-off in organised religion affiliation. It wasn't really talked about very much, but it was very stark and we saw the growth, in 2011, completely against what people had expected. People had been speculating that there might be a majority non-white British city and they thought Leicester might just about do it, 2011 census comes out and about 15 cities had it; London was a White minority ethnic city. No-one knew that was coming, it was a complete surprise to most researchers, so every census holds a mirror up and we find out new things about ourselves, which is what I'm excited and looking forward to seeing.

How does GEOLYTIX use the census?

We use the census in many different ways, from the very obvious, so just saying how many people are where is the basis of most of our demand models and then for the demographic characterization although there are many other techniques of trying to say who likes buying what, the census because of its multi-dimensional nature is one of the key building blocks. So one of the things the census does, unlike pretty much any other social research, is we do get these wonderful three, four-way tables so we can say we want to know how many professional, graduates living in rented accommodation, who are not in a relationship, that sort of four dimensions of a variable, you can get at small area in the census from the local characteristic tables. So that is how we characterize what sorts of people are living where and again, unlike some countries, we are also fortunate in that we have tremendous workplace data, so we collect where you work and again in these pandemic times it's going to be fascinating to see that new pattern, so when we try and work out anything to do with demand from the place of work, so coffee shops or Pret A Manger or bars or anything like that, we'll use the census in that and then also there's all sorts of alternative kind of edge-case uses that you will have for the census, so things like identifying second homes that might be a very niche thing but it's very important to a tiny little small use-case and because the census is so rich and provides data at such a small area, we are able to find all these edge use-cases. We also use the census in building some of our own data sets, so because it's open we can then take the census data, manipulate it, turn it into scales, use it to compare country against country, build up consistent data sets that we then use across all of our projects.

Will GEOLYTIX be processing up and releasing the 2021 census like the last one?

Absolutely. And it will be released as open data as the 2011 one was and we'll also be doing it across multiple countries. But, definitely the UK one we'll process it up, we'll put it into a nice flat pack, as we did in 2011 we'll pick what we think are kind of the top 2-300 variables because there's 30,000 variables that get reported in the census; if anyone wants all 30,000 they can have them, but we will pick the edited highlights and we will be getting that out available for you all to use as soon as we possibly can.

Blair Freebairn, CEO at Geolytix

Title logo by ONS

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