1. Data Management and Analysis John Hollis Demographic Consultant, GLA Data Management and Analysis Statistical Aspects

2. Data Management and Analysis Definitions Enumeration One Number Census Disclosure Control Content Outline

3. Data Management and Analysis Definitions 2001: Usual Residents –Does this mean me? –Easy to exclude oneself –Schoolchildren/students living away Solution: Enumerate all Usual Residents plus Visitors –Already decided –Need full clarification of the concept of ‘usual residence’

4. Data Management and Analysis Usual Residence: Issues Working away from home in week – family home Armed Forces – address when at base Shared Children – ‘majority’ time –May need to know both addresses Students- term-time Retired with two residences – ‘six-month rule’ Working abroad – UR if spent more than half of previous year in UK Communal Residents – ‘six-month rule’ Prisoners – ‘six-month rule’, but Remand are ‘visitors’

5. Data Management and Analysis Definitions Household Issues –Forget concept of ‘common housekeeping’ Suggest Household is: –One person, or –A group of people living at the same address and sharing cooking facilities OR some living space Other Issues –Dwelling –Multi-occupation (one residence with 2+ households) –Principal and Secondary Residences

6. Data Management and Analysis Enumeration Address List Problems –Not only Manchester and Westminster –No unique and accurate set Solution: link up OS/Royal Mail and IDeA (NLPG) –Needs rigorous and expensive checking Walk the streets –Important role for LAs to assist QA – 2007 Test Form Collection Issues –Single return post back address –Alternative ways to ‘be counted’ ie web/phone –Need better Management Information / Form Tracking

7. Data Management and Analysis One Number Census Comparator Data –Will NHS data be better than 2001? –Will ID Cards help? Will NPD help? Probably not entirely. –Do not assume that 2010 MYE will be correct! Demographic Analysis –Reliance on sex ratios – but 180k males added later –Will migration statistics have improved? Borrowing Strength –Unpopular fallback – a black box – need to use in extremis ‘Selling the Results’ –Gap year students? Males on Bondi Beach?

8. Data Management and Analysis Disclosure Control Low response –Undesirable - but a fact of life Imputation of missing records and variables –Necessary evil – problem for double geography Record swapping between areas –It may not be ‘me’ at all Combined categories for OA output variables Delay between enumeration and data release/use But we still had SCAMing imposed Hence ONC became ‘Pick a Number Census’

9. Data Management and Analysis Disclosure Control What do we need in 2011? High and unbiased response in all areas –Need for imputation minimised –But need for SDC increased All other SDC contained in the database –Therefore true ONC with: Internally consistent tables Consistent totals between tables Additive tables (ie OAs sum to LAs, etc) Consistent UK policy

10. Data Management and Analysis Content UK Harmonisation of Key Questions –Ethnicity –Religion 2011 Needs –Income –Language in the Home –Second Residence –Number of Vehicles – 2001, but Cat. 2 for 2011 –Place of Study (?) – Scotland only in 2001

11. Data Management and Analysis Summary LAs work with ONS on address lists and community liaison UK Consistency Users need a real One Number Census ONS – get SDC sorted out early and clearly