John Hollis Demographic Consultant, GLA

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

2. Outline • Definitions • Enumeration • One Number Census • Disclosure Control • Content

3. 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. 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. 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. 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. 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. 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. 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. 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. 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