Roundup of Census 2011 outputs event in Leicester

Office for National Statistics logoLast Thursday, I attended a Census 2011 outputs event.  It was hosted by the Office for National Statistics (ONS) in Leicester, and covered a range of Census-related topics.

I’ve highlighted key points from the event in this post.

The biggest proposed change to the Census in 2011, compared to 2001, is to open up access to the data. ONS want to move away from static tables towards dynamic tables, such as data cubes, that allow researchers to interrogate data more.

ONS propose to set up a Census databank that will allow users to manipulate data themselves. The databank will be accessed by ONS websites, such as Nomis and Neighbourhood Statistics, but ONS are also keen to let partners access it.

Partners would need to set up web-based user portals on their own websites to do this. However, it would enable Census data to be shared more widely – people could access Census data from a range of websites, outside of the ONS.

Disclosure and accuracy

However, giving users more control over data will create disclosure issues and affect the accuracy of data.

ONS said that some data entries would need to be swapped with comparable ones in other areas to prevent people being identified from the datasets.

They highlighted that data would be less accurate at lower levels of geography because, as disclosure risk increases, data unit swapping is needed more. Despite this, ONS plan to make data swapping smarter than in 2001.


The proposals made are dependent on funding, which is to be decided by HM Treasury by summer 2010. The ONS are currently putting together a bid to secure funding for their proposals, and welcome any funding partners can offer to deliver outputs.

ONS encouraged partners to send evidence on how Census 2001 data has informed a decision they’ve made or created an economic benefit. If you have any evidence to share, please email the Census team directly at

Census geography

Census geography was another interesting topic.

ONS hope to keep most of the 2011 Lower Super Output Area (LSOA) boundaries the same as 2001, to allow comparisons.

However, the population in some LSOAs has grown and the population threshold for LSOAs is between 1,000 and 3,000 people.

Therefore, some LSOA boundaries will need to change as they have exceeded the maximum population – ONS only expect this to apply to 0.4% of LSOAs, based on 2005 mid-year estimates.

ONS also said that some of the Output Areas in the 2001 Census were not ‘fit for purpose’, and invited partners to suggest any changes they felt should be made to Output Areas. Please email the Census team directly at

ONS also indicated that the Census 2011 will include new questions on national identity and language. The migration question has changed from 2001, and will draw out information on how long migrants intend to stay in England for.

Finally, a Census Rehearsal is currently taking place in Birmingham and three other cities to pilot the survey. The ONS hope to share findings from the pilot on their website, but did not give a release date for this.


One Response

  1. Naomi,
    Hi I attended the meeting in Leicester too. Just to add some additional information to your report. It was one of a series of seminars which marked the begining of consultation by ONS Census on the Outputs they are considering supplying for the 2011 Census ahead of a wider user Output Consultation.

    The biggest change they are working on is to provide data through dynamic tables (datacubes) and they are testing the implication of this to the potential disclosure of individuals. This may mean they have to do some more data swapping they have done in the past but we should be assured it will be done more intelligently than they did in the past. I don’t think they were suggesting NOMIS and Neighbourhood Statistics would be the the home of the census data but merely examples of the web sites that currently have portals to extract data from the census.They are hoping many more web portals will be able to extract census data direct from source in the future. If dynamic tables are provided there will also need to be controls over ‘drill-down’ so whilst providing detail for smaller areas for example there would need to be some aggregation of other categories and they want to explore what will be most useful to users.

    Whilst ONS has secured funding to run the census and process the data up to 2013 they have no money on the table after then. The period beyond 2013 is historically where most of the output and value added work takes place hence the call for support from users in developing their business case.

    LSOA boundaries MAY need to change if there has been a major increase(or decrease)in populaiton size AFTER the census but this will be restricted to splitting of individual LSOAs NOT a reshuffle of many boundaries as tended to happen in the past.

    Additionally ONS are providing the opportunity for organisations to nominate OAs/LSOAs for realignment where there are compelling reasons for this e.g. residential areas in LSOAs divided by rivers that have no means of contact across the river.

    Both the above would have to happen within the suggested 0.4% change.

    Part of Birmingham is involved in the census rehersal but only to test field management structures. The rehearsal will test Royal Mail’s contingency plans if postal strikes continue over next 6 weeks.


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