Data Management and Analysis

John HollisDemographic Consultant, GLA

Data Management and Analysis

Statistical Aspects

Data Management and Analysis

• Definitions

• Enumeration

• One Number Census

• Disclosure Control

• Content

Outline

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’

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’

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

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

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?

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’

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

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

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