Metrics for local authority assessment framework

Page last updated: 4 December 2025

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Demographic data

Upper tier local authority population

  • Item full description: Population by upper tier local authority, by:
    • Overall population (all ages)
    • Young population (0 – 17 years)
    • Working population (18 – 64 years)
    • Older population (65 + years)
  • Numerator:
    • Overall population (All Ages)
    • The number of people aged 0-17
    • The number of people aged 18-64
    • The number of people aged 65 and over
  • Denominator: N/A
  • Observed: N/A
  • Item Type: Count - Raw counts with no other contextualising values
  • Data source: Office for National Statistics - Mid-Year Population Estimates, UK

Data are for upper tier local authorities in England only. Estimates are presented unrounded. Unrounded estimates are published to enable and encourage further calculations and analysis. However, the estimates should not be taken to be accurate to the level of detail provided. More information on the accuracy of the estimates is available in the Office of National Statistic’s Quality and Methodology document (QMI).

% of people from a specific ethnic group

  • Item full description: The percentages of people whose ethnic group comes under one of these 5 categories:
    • Asian or Asian British
    • Black, Black British, Caribbean or African
    • White
    • Mixed or Multiple
    • Other
  • Numerator: The number of people whose ethnic group is:
    • Asian or Asian British
    • Black, Black British, Caribbean or African
    • White
    • Mixed or Multiple
    • Other
  • Denominator: The sum of people from all 5 ethnic groups
  • Observed: Numerator/denominator
  • Item Type: Proportion
  • Data Source: Office for National Statistics - Census 2021

Data are for upper tier local authorities in England only.

Index of Multiple Deprivation

This metric shows the Index of Multiple Deprivation (IMD) decile based on the IMD average score for each upper tier local authority. The average score is the population weighted average of the combined scores for the Lower-Layer Super Output Areas (LSOAs) in a larger area. This measure is calculated by averaging all the LSOA scores in each larger area after they have been population weighted.

The average score is presented within a decile. A decile refers to splitting up a set of ranked data into 10 equally large subsections of 10 percentage points. A decile of 1 means the most deprived (most deprived 10% of local authorities) and a decile of 10 means the least deprived (least deprived 10% of local authorities) subsections of 10 percentage points.

The local authorities are also ranked by their average score from 1 to 153, from most deprived to least deprived.

Upper tier local authorities are as at April 2023 boundaries.  

Life Expectancy at Birth (3-year range) - Female

  • Item full description: Life Expectancy at Birth (3-year range) - Female  
  • Item Construction: Age-and-sex-specific mortality rates are calculated in 5-year age ranges, standardised methodologies are applied to determine average life expectancy from birth
  • Item Type: Continuous
  • Data source: Department of Health & Social Care - Fingertips: Public Health Profiles

This metric shows the average number of years a female person would expect to live from birth based on mortality rates over three years, by Upper Tier Local Authority. For a particular area and time period, it is an estimate of the average number of years a newborn baby would survive if she experienced the age-specific mortality rates for that area and time period throughout her life.

Figures are not calculated for City of London or Isles of Scilly due to small numbers of deaths and populations.

Life Expectancy at Birth (3-year range) - Male

  • Item full description: Life Expectancy at Birth (3-year range) - Male
  • Item Construction: Age-and-sex-specific mortality rates are calculated in 5-year age ranges, standardised methodologies are applied to determine average life expectancy from birth  
  • Item Type: Continuous
  • Data source: Department of Health & Social Care - Fingertips: Public Health Profiles

This metric shows the average number of years a male person would expect to live from birth based on mortality rates over three years, by Upper Tier Local Authority. For a particular area and time period, it is an estimate of the average number of years a newborn baby would survive if he experienced the age-specific mortality rates for that area and time period throughout his life

Figures are not calculated for City of London or Isles of Scilly due to small numbers of deaths and populations

Inequality in Life Expectancy at Birth - Female

  • Item full description: Inequality in Life Expectancy at Birth (Female) Slope Index of Inequality – Years
  • Numerator: N/A
  • Denominator: N/A  
  • Observed: Age-and-sex-specific mortality rates are calculated for each LSOA and aggregated into deprivation deciles for a Local Authority. Standard methodologies are applied to estimate life expectancy at birth in each decile, and from there the estimated difference between most and least deprived areas within a Local Authority is calculated
  • Item Type: Continuous
  • Data source: Department of Health & Social Care - Fingertips: Public Health Profiles

Inequality in life expectancy at birth is the estimated difference in life expectancy between Local Authorities in the least and most deprived deciles where deprivation is based on the Index of Multiple Deprivation.  

Life expectancy at birth is calculated for each deprivation decile of Lower Super Output Areas (LSOAs) within each Upper Tier Local Authority and then the slope index of inequality (SII) is calculated based on these figures. The SII is a measure of the social gradient in life expectancy, that is how much life expectancy varies with deprivation. It takes account of health inequalities across the whole range of deprivation within each area and summarises this in a single number. This represents the range in years of life expectancy across the social gradient from most to least deprived, based on a statistical analysis of the relationship between life expectancy and deprivation across all deprivation deciles.

Life expectancy at birth is a measure of the average number of years a person would expect to live based on contemporary mortality rates. For a particular area and time period, it is an estimate of the average number of years a newborn baby would survive if she experienced the age-specific mortality rates for that area and time period throughout her life

Figures are not calculated for City of London or Isles of Scilly due to small numbers of deaths and populations.

Inequality in Life Expectancy at Birth - Male

  • Item full description: Inequality in Life Expectancy at Birth (Male) Slope Index of Inequality – Years
  • Numerator: N/A
  • Denominator: N/A
  • Observed: Age-and-sex-specific mortality rates are calculated for each LSOA and aggregated into deprivation deciles for a Local Authority. Standard methodologies are applied to estimate life expectancy at birth in each decile, and from there the estimated difference between most and least deprived areas within a Local Authority is calculated.
  • Item Type: Continuous
  • Data source: Department of Health & Social Care - Fingertips: Public Health Profiles

Inequality in life expectancy at birth is the estimated difference in life expectancy between Local Authorities in the least and most deprived deciles where deprivation is based on the Index of Multiple Deprivation.  

Life expectancy at birth is calculated for each deprivation decile of Lower Super Output Areas (LSOAs) within each Upper Tier Local Authority and then the slope index of inequality (SII) is calculated based on these figures. The SII is a measure of the social gradient in life expectancy, that is how much life expectancy varies with deprivation. It takes account of health inequalities across the whole range of deprivation within each area and summarises this in a single number. This represents the range in years of life expectancy across the social gradient from most to least deprived, based on a statistical analysis of the relationship between life expectancy and deprivation across all deprivation deciles.

Life expectancy at birth is a measure of the average number of years a person would expect to live based on contemporary mortality rates. For a particular area and time period, it is an estimate of the average number of years a newborn baby would survive if he experienced the age-specific mortality rates for that area and time period throughout his life.

Figures are not calculated for City of London or Isles of Scilly due to small numbers of deaths and populations.