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Review of migration methods using health registrations. Nick Wright Cecilia Macintyre General Register Office for Scotland. Overview of Presentation. Description of method of estimating migration for areas in Scotland Comparison of NHSCR and CHI estimates Developments in sources
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Review of migration methods using health registrations Nick Wright Cecilia Macintyre General Register Office for Scotland
Overview of Presentation • Description of method of estimating migration for areas in Scotland • Comparison of NHSCR and CHI estimates • Developments in sources • Future work
Sources of data used in internal migration • NHSCR Movements are recorded between Health Board Areas and UK countries • CHI movements allow migration to be measured below health board area
NHSCR • Originally set up in 1939 for purpose of call-up for military service and food rationing • Function - to maintain a register of all NHS patients on lists of general practitioners in Scotland • To supply info to organisations in health service and for medical research
NHSCR • Currently holds records for every patient registered, now or in the past with a Scottish GP • Everyone born in Scotland since 1985 who have not been registered with a Scottish GP • Patients formerly registered with a Scottish GP, who died after 1992
NHSCR dataset • Unique NHS number • Unique Community Health Index number • Names • Date of birth • Current and previous registrations with UK health authority • Medical flags
NHSCR migration data • Monthly files provide individual records for all changes in posting with age and sex • Scottish Health Board • England & Wales Health area • Northern Ireland • Armed Forces • Immigrants and embarkations
Community Health Index • All patients registered with a GP in Scotland, or those in contact with health service allocated CHI number • Since 1997 there has been a unique CHI number allocated • Aim to use throughout health service for identification
CHI annual extract • Information includes • CHI identifier (anonymised ) • Current status • Age/sex • Health board of residence + Postcode • Transfer in/out dates + Area codes • Immigrant code
CHI processing(1) • CHI extract (1) • Select currently registered patients • CHI extract (2) • Select currently registered patients and those ‘leaving’ within last year
CHI processing(2) • Match two extracts using unique CHI • Current patients in both extracts • Current patient in extract 1 but not in extract 2 • Current patient in extract 2 but not in extract 1 Use information on postcodes and postings to allocate migration at lower level
Research questions • Require to understand relationship between two sources • NHSCR will be extended to include postcode updates from CHI, proving a new single source • Understand impact of changes in methods
Issues to consider in understanding patterns • Differences in what is being measured • Counts of events (NHSCR) • Change in status one year apart • Exclusion of some situations e.g. cancelled records • Impact of multiple movements within a year
Patterns of short term cross-border migration • Current approach of identifying in migrants on CHI will undercount total because of moves within year • Identified new patients on second CHI extract who had moved within the year
So what? • Current allocation of in-migrants to Scotland from Rest of UK will use distribution of migrants who do not move subsequently • Require to compare this with the destinations of people to move more frequently
NHSCR extract development • Transfer of Scottish NHSCR system has provided opportunities • Additional fields on database • Additional capability for analysis
NHSCR extract (2) • New fields on database will include • Postcode (updated through CHI system) • Country of Birth
NHSCR extract (3) • Additional capability for analysis • Project underway to receive monthly extract from NHSCR system • Details of all people on system • Complete history of postings • Complete history of postcode from 2008 onwards