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Background on the nature of the Census and outline its importance todayProvide overview of the types and structure of the Census statistical outputsLook at Census geographyDiscussion of its limitations and strengths. Topics covered in this lecture. Introduction. OriginWhat's the point?Administrative issuesTaking stock Basis for economic and social policies?Scientific researchWhat is it? Any problems with it? .
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1. Introduction to the Census Introduction
What is it?
What is covered?
Rationale for conducting a census
UK Census
Changing focus of the census
The 2001 census
Census output
Census geography
Problems with the census
Conclusion: Limitations and strengths
Appendix: Access to the data
2. Background on the nature of the Census and outline its importance today
Provide overview of the types and structure of the Census statistical outputs
Look at Census geography
Discussion of its limitations and strengths Topics covered in this lecture
3. Introduction Origin
What’s the point?
Administrative issues
Taking stock
Basis for economic and social policies…
Scientific research
What is it?
Any problems with it?
4. What is a Census? The Census is a simple questionnaire survey administered by the government to all people in the UK on a single day
Aim: Total enumeration of the population (i.e. a complete head count) at a single point in time
Unique survey that provides national coverage
Collects factual (‘objective’) data, not subjective opinions
Self-completion and self-identification of the ‘facts’
Problem whether people fill it out accurately, subject to their interpretation of questions, do they lie?
5. Subjects covered by the Census
Demographic characteristics (age, sex, martial status)
Household relationships
Household accommodation
Migration
Employment
Work place
Journey to work
Education and qualifications
Health, provision of care
Cultural characteristics
Ethnicity
Language
Religion
Seeking ‘facts’, not opinions or feelings
6. Rationale for the Census Best picture of the state of people, households and homes in the UK
Describes all people with uniform, consistent levels of accuracy
Simple questionnaires are translated into large number of derived statistics
7. Rationale for the Census Vital for policy analysis and used directly in calculating the allocations of billions of pounds of public expenditure (Ł60 billion figure quoted)
Used to determine grants to local authorities and health trusts
Census results have real world consequences
Census “is still the bedrock of many a consumer research sample and the skeleton on which the numerous commercial classifications … are constructed.” retail planning, target marketing
The Census is the most important secondary data source for academic researchers, especially for geographers
Describes the detailed demography for small areas across the whole country vital for quantitative geographic analysis
No other data sources provides such comprehensive spatial coverage.
8. Rationale for the Census Construction of flow data
Movements of people between small areas
Commuting patterns
Migration patterns
Used to explore the nature of relationships between demographic and socio-economic variables across space
It is the bench mark for other sample surveys (a kind of ‘gold standard’)
Important in calculating statistical rates (provides denominator)
Mortality rates
Disease rates
Unemployment and employment rates
Census variables are combined to indices of deprivation
9. Census and confidentiality Vitally important to protect personal information
The Census forms are collected and processed in secure conditions. The Census Confidentiality Act 1991 gives legal protection by making the unauthorised disclosure of personal Census information a criminal offence (i.e. you will go to prison if violated)
Same is true for Economic censuses, …
Aggregation of individual values to a spatial scale where no personal identifiable data about an individual or household is discernible
Statistical blurring of small counts in small area
Individual data kept securely and only released after 100 years (1901 is now online)
Think about how might need to guarantee anonymity to people you interview in your dissertation research
10. UK Census Many countries carry out a national census (others do rolling surveys)
UK Census is held every 10 years, at the start of each decade
A Census has been held every decade since 1801 (except 2nd World War)
1801 Census
5 questions
10 million people living in 2 million households
Rapid population growth and fear of overcrowding (‘Malthusian’ population crisis)
2001 Census
46 questions
60 million people
1901 Census is online and can search for your family, http://www.census.pro.gov.uk
11. Changing focus of the Census
12. The 2001 Census Most recent Census was held on 29th April 2001
Census 2001 revealed UK population was 58,789,194
Response rate was 95%
Legally required to complete it (Ł1,000 maximum fine, but only 38 successful prosecutions)
Very complex to plan, administer and to process and release data
Estimated costs of Ł259 million
Questionnaire design and wording thoroughly tested
Temporary work force of about 70,000 people, inc. 62,500 census enumerators who hand deliver the forms
Data entry and processing took over a year, some specialised results only released in 2004
13. Innovations in 2001 Census Post back of the forms
‘One Number Census’
Imputation for people missed or did not complete a form
100% coding of the data from the forms.
1991 Census: much of detail was only coded for 10% sample
Census access programme
Free and easy access to all results, big contrast to previous years
Much quicker release of results
New structure of output geography based on postcodes (designed by geographer David Martin, University of Southampton)
15. Was completed by all (or virtually all) 20+ million households in the country
Needs to be as simple and clear as possible
Self completed survey
Quite short
10 household questions
36 individual questions 2001 Census questionnaire
16. Tricky census questions No question on household income!
Assumed it would scare people off or invite false answers
Most important missing question
Scientists want to include it for the 2011 (but unlikely)
Preparations for the 2011 census already underway
Religion question is optional as it is seen as somewhat controversial
Campaign to get people to put down Jedi – 4th largest religious group in UK!)
What might be some of the problems asking this question?
What implications for areas/neighbourhoods
Ethnic group membership question is problematic
What does ethnicity mean?
Health questions are problematic
Subjective
Potential for misuse of information by insurances,…
How to complete free form answers?
What other types of questions would you ask?
Difficult to add new questions to the Census
18. From questions to statistical counts From the individual answers a large number of cross tabulations are calculated to give individual variables or counts
40 questions generate 2 billion bits of data
number of students in Camden (uni-variant count)
number of students, by age groups (21-24, 25-29, etc)
number of male students, by age groups 21-24, 25-29,
Large number of possible cross-tabs
Only a small number are calculated and published
The cross tabulated data are aggregated to areas for publications
19. Census data outputs printed reports
national monitors and country reports
topic based reports (e.g. housing)
20. Area-based statistics Aggregated data are summarised in tables
Each table covers a particular theme
A table contains many predefined set of standard cross-tabulations of two or more variables
Several types that vary in their level of detail
number of topics
number of cross-tabulation
smallest spatial unit
Trade-off between geographic and statistical detail (strict rules on confidentiality)
21. Table types Standard Tables
most detailed, 119 tables giving 75,000 variable. available for wards or larger units
Census Area Statistics
general purpose, 143 tables giving 15,000 variables. available for Census output areas and larger spatial units
Key Statistics
useful overview, 31 tables, 400 variables. available for Census output areas and larger spatial units
Profiles
overviews, aimed at particular users. available for parishes, parliamentary constituencies and postal sectors (WC1E 6)
Headcount
just a count of people, and households in each postcode
26. Census geography
27. 2001 census output units in England & Wales
42 counties (e.g. Inner London)
376 districts (Boroughs, e.g. Camden)
8868 wards (e.g Bloomsbury)
175,434 output areas (OAs)
80% contain between 110-140 households Census data are aggregated and made available for a number of geographical areas in England and Wales (things vary in Scotland) in 1991 including: counties, health authorities, local authority districts and also small areas known as wards and enumeration districts (EDs) (Cole, 1993). EDs were the basic building blocks used for the 1991 (and 1981) Census for both collecting and disseminating data. An ED contains about 200 households on average and is the smallest zone at which Census data are made available. EDs aggregate perfectly into wards, districts and finally counties at the top of the hierarchy, illustrated above in Box 3.
In 2001 EDs were used for fieldwork and data collection purposes, whilst specially designed 'outputs' areas are being used for disseminating data.
Census data are aggregated and made available for a number of geographical areas in England and Wales (things vary in Scotland) in 1991 including: counties, health authorities, local authority districts and also small areas known as wards and enumeration districts (EDs) (Cole, 1993). EDs were the basic building blocks used for the 1991 (and 1981) Census for both collecting and disseminating data. An ED contains about 200 households on average and is the smallest zone at which Census data are made available. EDs aggregate perfectly into wards, districts and finally counties at the top of the hierarchy, illustrated above in Box 3.
In 2001 EDs were used for fieldwork and data collection purposes, whilst specially designed 'outputs' areas are being used for disseminating data.
31. 32 Output Areas in Bloomsbury(24,140 Output Areas in London)
32. Problems with the Census Census data goes out of date quickly
Expensive (259 million Ł)
Time burden on 50 million people
Only “objective” facts
Range of questions asked is limited (still no income question)
Problems with comparison over time (changing questions, geography)
People missing from the census (undercount)
33. Census undercount People not counted (‘Missing millions’)
2% estimated to be missed by 1991 census
Not evenly distributed through social groups or across space
Westminster council claims to have ‘lost’ 65,000 people they expected
Important as it effects the allocation of resources
poorest areas tend to get hardest hit
High non-response rates are found for:
young people, especially men; students
recent migrants
unemployed
minority ethnic groups
private renters
those who share a dwelling
babies
34. Census or senseless data ?? Can be confusing!
Lots of boring technicalities
Data itself is pretty boring
But it is very useful as the data enables you to do interesting analysis
Likely that many of you will want to use census data in your dissertations
Be prepared to invest some time to find the right data, extract it and process it
35. Conclusion: Strengths and weaknesses STRENGTHS
‘Gold standard’ data source
Objective and consistent description of all people
Geographically comprehensive data at range of geographical scales
Consistent data for small areas
Has the confidence of people and data users
WEAKNESSES
Census data goes out of date quickly. only once every 10 years
Expensive
Only “objective” facts
Undercount)
Limited range of questions
Problems with comparison over time
36. How can you access census data? published statistical summaries on http://www.statistics.gov.uk/census2001/census2001.asp
full tables downloadable in Excel format from Neighbourhood Statistics website
specifically for universities is the Census Dissemination Unit (CDU) at MIMAS (http://www.census.ac.uk/cdu)
register & access for free using Athens account
statistical data of the 1981, 1991 and 2001 Censuses through the CasWeb service
Strict licensing agreements/undertakings govern all use of Census data and exist to protect individual privacy and crown copyright; for more information, see the Census Disseminaton Unit website.
However, as long as you are studying or researching in an UK University or College, you can access Census data for free. Academic users can access the 1991 and 1981 census from MIMAS, using CASWEB or SASPAC
Strict licensing agreements/undertakings govern all use of Census data and exist to protect individual privacy and crown copyright; for more information, see the Census Disseminaton Unit website.
However, as long as you are studying or researching in an UK University or College, you can access Census data for free. Academic users can access the 1991 and 1981 census from MIMAS, using CASWEB or SASPAC
38. Organisation of the UK census Census varies slightly in different countries of the UK. some different questions - language, religion, ethnicity
Focus on England and Wales
Sight variation in output census geography
Some variation in the published census outputs
39. More information on the Census
40. www.chcc.ac.uk/CAS/resources.html
42. Key reading for this Lecture(very useful for the course assessment!) Boyle P, Dorling D, 2004, “The 2001 census: remarkable resource or bygone legacy of the ‘pencil and paper era’? Area, 36(2) 101-110
download from http://www.geog.ucl.ac.uk/~jessletzbichler/geog2003/boyle_dorling2004.pdf
43. Next week Monday: Exploratory data analysis - percentages, charts, histograms and correlation
Tuesday: Census data analysis