The ONS Longitudinal Study - plans for the 2011 Census and beyond Jim Newman, Head of Longitudinal Study Development, Office for National Statistics

Outline Overview of the ONS Longitudinal Study (ONS LS) Plans to link 2011 Census data to the ONS LS Future of the ONS LS after the 2011 Census ONS LS resources and further information

Definition of the ONS LS ‘The ONS Longitudinal Study is a study containing linked census and life events data on a one per cent sample of the population of England and Wales.’ Note: A study, not a survey

Structure of the ONS LS 1971 Census 1981 Census Entries Linked events 530,000 sample members selected 513,000 traced 1981 Census 536,000 sample members selected 528,000 traced 1991 Census 544,000 sample members selected 535,000 traced 2001 Census 540,000 sample members selected 536,000 traced 2011 Census 5??,000 sample members selected 5??,000 traced Entries 264,000 new births 164,000 immigrants Exits 233,000 deaths 39,000 emigrants Linked events 253,000 births to sample women 2,000 infants deaths to sample women 80,000 widow(er)hoods 110,000 cancer registrations

Census samples available for analysis 1971 1981 1991 2001 513,000 528,000 535,000 536,000 1 census 408,000 420,000 2 censuses 418,000 327,000 3 censuses 331,000 256,000 4 censuses Total traced LS members: 1,036,000

Study cycle of an LS member 1950 1970 1980 2010 1990 2000 2001 Census 1991 Census 1981 Census 1971 Census Born 1955 Entry Birth #1 Birth #2 Events Exit Re-entry Death of spouse Cancer Death (Exit from study)

Census data Life event data ONS LS data What does the ONS LS contain ? Geographic data Ethnicity (1991 & 2001) Self-rated health (2001) Long-term limiting illness (1991 & 2001) Religion (2001) Care giving (2001) Migration & travel to work Education (all levels 2001) Census data Marital status & family type Housing & amenities Occupation & social class Economic activity Life event data Infant deaths to sample mothers Still births to Live births to Widow(er)hoods Immigrations Emigrations (recorded) Births of ONS LS members Cancer registrations Deaths (cause specific) Age, sex & country of birth

High level plan to link 2011 Census data Census Day, 27 March 2011 2 Delivery of 2011 Census link extract data files starts, one per delivery group 3 Delivery of full 2011 census data extract 4 Reporting to 2011 Census QA begins 5 Final processing report to Census QA covering all delivery groups 6 Full ONS LS census-to-census linkage analysis complete (equivalent to LS10 from 2001 Census) 7 Beta testing of ONS LS database incorporating 2011 Census data starts 8 Launch of ONS LS database incorporating 2011 Census data starts

2011 Census quality reporting Post-2001, ONS LS-based adjustment to population estimates 2011 Census, report to Census during processing Undercount who didn’t appear in the census, broken down by: age sex location marital status ethnicity, etc. Overcount who appeared more than once in the census, and why within household multiples, e.g. internet and paper response students at home and term-time addresses people at home and communal establishment movers enumerated at old and new addresses children of separated parents at both addresses, etc.

Questions in the 2011 Census New questions in 2011: second residence number of bedrooms civil partnerships Questions being asked for the second time in 2011: caring responsibilities self-rated health religion

Questions in the 2011 Census Questions on the themes of nationality/ethnicity/migration/religion: country of birth if born abroad, month and year of arrival to live in UK (’71) if arrived in the preceding year, intended length of stay (new) national identity (new) ethnic group main language (new) religion address one year ago passport held (new)

Future direction for the ONS LS Short to medium term Fully exploit the new LS database Expand LS user base, particularly within Government Update annually with a fifth decade of life events data Closer integration with sister studies in Scotland and Northern Ireland Long term What will we do in 2021?

Centre for Longitudinal Study Information and User Support LS resources and further information ONS website www.ons.gov.uk/about/who-we-are/our-services/longitudinal-study Centre for Longitudinal Study Information and User Support www.celsius.lshtm.ac.uk