There’s much more to the census than the size of the population...

Deputy director for census at the Office for National Statistics, Pete Benton. Picture: Paul Jacobs (143472-1)
Deputy director for census at the Office for National Statistics, Pete Benton. Picture: Paul Jacobs (143472-1)
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The census is a vital piece of research carried out once a decade by the Office of National Statistics, which has an office in Titchfield. Kimberley Barber went along to find out how they go about it and why it’s so important.

It’s a massive undertaking which costs £480m and involves every household in the country.

4/12/14    Agenda''Office for National Statistics in Titchfield - ''Picture: Paul Jacobs (143472-7) PPP-140412-162336001

4/12/14 Agenda''Office for National Statistics in Titchfield - ''Picture: Paul Jacobs (143472-7) PPP-140412-162336001

It employs 35,000 ground staff, its results shape many important government decisions and it’s all organised in a building in Titchfield.

The census, which is carried out every 10 years, is a big deal. That’s why I’ve come to visit the Office for National Statistics to find out more.

Deputy director for census, Pete Benton, from Park Gate, has worked at the ONS for 12 years. His job is to oversee the operation.

He says: ‘People don’t realise quite what goes on here. They fill in the form and send it back every 10 years, but to us it is 10 years of hard work and the result is fantastic numbers that help Britain run and we are doing that here. It is of such huge value to society.’

The results from the census look at all aspects of how we live in this country, from where we work, to how we get to work, who lives in our households and what they look like. It forms a crucial part of where and how the government spends its money – totalling £699bn in 2010 alone.

Pete says: ‘All this spending depends on understanding the population. You cannot plan a health service if you don’t know the numbers that you are planning it for.

‘The population grew by 10 per cent in the last decade and it grew in different ways than before in different bits of the country so the pressure on the service is in different places.

‘Similarly with education – where do you need schools? Well you need them where the kids are.

‘The census underpins all kinds of decisions across the government. And it’s not just once every 10 years, as in between we update it.

‘We know who has come into the country, we know who has left, we know who has been born and who has died from one census to the next and you can estimate the change and use those figures.

‘But you can never do that perfectly and you need the census every 10 years to get you back on track.’

And it’s not just used in education and health, it also helps decide where houses are needed and what transport they need.

Its figures are also used by many private sector companies.

Pete says: ‘The census tells us about overcrowding and how many people there are in an area, how many houses and bedrooms there are and helps to work out where to put houses.

‘It also tells you about transport, where people live, where they go to work and how they get there. All that feeds into the public sector but also the private sector, like supermarkets.

‘If they didn’t know information like that they would be putting the wrong things on the shelves. They would be putting nappies on the shelves of a supermarket where pensioners live. They really do change what’s on the shelf according to the census.’

The census has been running since 1801 and has changed over the years.

Pete says: ‘2011 was considered the best census of modern times. We did a good job which was helped by that fact that the sun shone. We had a beautiful spring and we had people out knocking on doors to collect forms and people were happy to answer the door and fill in the forms in. We had a bit of good luck as well but we did a good job of it.

‘We won quite a few awards. We won an award from the Demographic User Group, which is made up of commercial users like John Lewis and Sainsbury’s.

‘They gave us an award for how we did the census. We won an award from the major project authority, which oversees all major government projects, for a successful government project It was a good job done.’

In total the ONS gathered information from 24m households by sending out 35m questionnaires, getting a 94 per cent response rate.

But how did they know they had only counted 94 per cent of the population?

Pete explains: ‘By definition the census tells you how many people you have got so you know how many people have replied but not how many have not responded. Well we have a statistical way of solving that problem.

‘Imagine you have a pond and you want to count how many fish there are. You could drain the pond but that would kill all the fish.

‘Supposing you go fishing and catch as many as you can. I catch 100 fish and put a red tag on them all and throw them back. The next day I go fishing and catch 50 fish of which half have a red spot on them. That’s another 25 I’ve found out there’s 125 but there’s probably a few more lurking.

‘But from that information you now know how many fish there are in the pond. That probably means that half the fish in the pond have got a spot on them so there will be 200 in the pond as half the pond was marked in the first count.

‘That’s what we do in the census. We do the census and then four weeks later go out again to one per cent of the postcodes and we count everybody again.

‘We can then see who we counted first time, second time and just doing that fish-in-the-pond formula we can still say that although we didn’t count everybody, we have an accurate number.

‘We don’t just count, we have to do a bit of fiddling around the edges to make sure the numbers are correct.’

The ONS employs 35,000 ground staff for six weeks to collate the information.

Around 70 per cent of people will in the census straight off but the remaining 30 need chasing and the ground staff knock on doors and explain the benefits.

And even though we are still some way off until the next census in 2021, about 100 staff are still working on the figures and preparing for the bout of hard work.

Pete says: ‘Last time we managed to get 94 per cent of responses so we could produce some fantastic statistics.

‘In total we produced about 6bn numbers and we are still going. It’s a beast. It’s described as the biggest peace time government operation and it’s probably true. What else has mobilised 35,000 people and all 24m households in the UK to do something at the same time?’

What the ONS does

The Office for National Statistics is the UK’s largest independent producer of official statistics and is the recognised national statistical institute for the UK.

It is responsible for collecting and publishing statistics related to the economy, population and society at national, regional and local levels and also conducts the census in England and Wales every 10 years.

It is the executive office of the UK Statistics Authority and although they are separate, they are closely related.

ONS has three sites - Titchfield, Newport and London.

It publishes its figures and graphs online at

Next Tuesday’s Agenda in The News will be looking at how it collates its birth, death and marriage statistics and what it does with that information.

The future of the census

AS technology advances and makes it easier to store and reference big data is the census still needed or could its £480m be better spent?

Everywhere we go we are asked to give over details. Our doctor holds our most personal details, but so do dentists, employers, tax records, numerous websites and even supermarkets.

But Pete Benton, deputy director of census at the Office for National Statistics, says the census is still relevant.

He says: ‘What we found is that you can get some of the way but not all of it.

‘For instance, some people have a national insurance number and they emigrate so the list of people with a national insurance number is not the same as the people who live in the country.

‘We have done quite a lot of work to see if we could use that information but we found that it’s not accurate.

‘But we are trying to find more intelligent ways of using that information.’

Technology is also having an impact on how the census is collated.

The 2011 census was the last time that paper surveys are used with the census moving online.

Pete says: ‘Everybody will be asked to do it online. We know that some people will need support or will still need a paper form and we are preparing for that.’

It’s not just the physical form of the census that has changed, the type of questions has also changed.

Pete says: ‘Back in the 50s we were asking people if they had a bathroom inside their house; well we don’t need to ask that any more.

‘But at its heart it is a count of the population.’

Population ebbs and flows

NUMBERS can paint poignant pictures and there could be none more moving than the ones that depict the tragic loss of life caused by war.

The devastating impact of sending thousands of young men to fight for their country can be seen in graphs produced by the Office for National Statistics.

Deputy director of census Pete Benton explains: ‘Over 100 years we have gone from a beautifully ordered pyramid of people to a population that goes in and out.

‘That is poignant to look at the gap because of the people killed in the war. You can see it in pictures how our society has changed because of wars and migration.

‘It really strikes me.’