POPULATION MANUAL
PROPOSAL FROM EMPHO ANALYSTS FORUM
BACKGROUND
There is considerable variation between local and national population sources for GP
registered and resident populations. This has caused difficulties for public health
practitioners across the whole of the East Midlands, resulting in confusion over
knowing which populations to use and when to use national or local populations.
This was raised as an issue of concern at the first EMPHO analysis forum and it was
agreed that a sub-group would meet to discuss the issues and propose a way
forward. It was agreed that this sub-group would develop a population manual for
use across the East Midlands area with common definitions and methodologies for
public health analysis.
RESIDENT POPULATIONS
Definition of Terminology
Resident Relevant Population – Population with a usual address within a
geographical boundary of an SHA; PCO; excluding special populations, adjusted to
ensure consistency with ONS estimates for local authorities (i).
Special Populations – Special populations are made up of armed forces (including
their dependants) and convicted prisoners who have served more than six months of
a prison sentence (i).
Defining the PCT Resident Population
The PCT resident population is the population that lives within the geographical area
of a PCT, excluding the special populations. The Department of Health publish PCT
resident populations on an annual basis by quinary age bands. These populations
are based on GP patient registration data, extracted from Family Health Service
(FHS) registers at postcode level and reconciled to the Office of National Statistics
(ONS) Local Authority population estimates. These population figures are used by
the Department of Health and the National Centre for Health Outcomes
Development to produce data for the Compendium of Clinical and Health Indicators.
As these are nationally recognised populations this is the preferred resident
population base for PCTs across the East Midlands.
Ward Level Resident Populations
Ward level populations have not historically been published on an annual basis by
ONS. Also, when ward population projections have been made available they have
not been made available by age and sex. This is a major factor in the use of locally
derived populations as publication of population data at ten-year intervals from
census data is not suitable for local data analysis.
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ONS are planning to produce ward level mid year estimates by age and sex. This
will provide a ward level population base that is consistent with the PCT resident
population figures. The current denominator for ward level populations is 2001
census data. The preferred ward level population for PCTs will be the ONS
population once this is available.
Coterminosity of Ward Boundaries with PCT Boundaries
PCT boundaries are defined as part of their statutory instrument. They are all
coterminous with ward boundaries at the time of their establishment order. However,
there has been a major ward boundary review and PCT boundaries are not
coterminous with ward boundaries. As a result, ward level population estimates (and
the 2001 census data) cannot be aggregated into PCT populations.
It is anticipated that the rules around the definition of PCT boundaries will be
changed in the future as there is an issue highlighted by ONS around disclosure and
small areas. EMPHO is compiling a database of statutory instruments that will track
the changes in ward boundaries and any changes to PCT boundaries. This is an
issue that will have to be reviewed as further guidance becomes available.
REGISTERED POPULATIONS
GP Relevant Populations
The GP relevant population is the population registered with a GP constituent
practice of a PCO and SHA; excluding special populations, adjusted to ensure
consistency with ONS estimates for Local Authorities (LAs) (ii).
These populations are published by the Department of Health on an annual basis.
There is a considerable difference between the Department of Health populations
and populations reported by PCTs for their registered populations. It was agreed
that for the purposes of comparability and consistency across the region the
Department of Health published populations would be used wherever possible. If
PCTs are analysing data by GP or by practice a judgement needs to be taken about
the appropriateness of using populations derived directly from the FHS register or
whether to standardise these back to the National PCT populations by age and sex.
Using FHS Populations
There are a number of cases where there is a clear need to use GP registered
populations extracted from the FHS register. These cases clearly defined by the
Department of Health and include immunisation uptake rates, breast screening
uptake rates and cytology uptake rates. The definitions for defining these rates and
their associated populations are clearly set out by the Department of Health in their
data definitions for central returns. If data is collected centrally for reporting the NHS
data definitions should supersede the rules set out in this document.
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SUMMARY
This document aims to set out a broad set of rules to allow a standard approach to
population definitions across the East Midlands. This, along with using standard
methodologies, will allow the work programmes defined across the PCTs in the
region to generate comparable data. There will always be cases where a common
approach will not fit requirements and if there is a situation that does not fall within
the guidelines set out here, advice is available from local public health analysts.
Membership of Population Sub-Group
Janine Milligan – LNR SHA
John Langley – EMPHO
Hanna Blackledge – Leicestershire HIS
Eyan Dodd – Lincolnshire HIS
Jean Robinson – Nottingham HIS
Kristina McKormick – Rushcliffe PCT
Graham Gardner – Nottingham City Council
Richard Cooper – Nottingham City Council
Rob Ward – Derby
(i)
Resident Relevant Populations: Local area estimates (less armed forces and prisoners) –
Department of Health, December 2002
http://www.doh.gov.uk/stats/population/ads202-resident-population-technote.pdf
(ii)
GP relevant populations; local area estimates, Department of Health, December 2002,
http://www.doh.gov.uk/stats/population/ads2002-gp-population-technote.pdf accessed
November 2003
PHM/JM/EMPHO Analysts/Population Manual-Proposal from EMPHO Analysts Forum – 11.11.03
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