Segment Tool

Segment Tool

Introduction

This tool provides information on the causes of death and age groups that are driving inequalities in life expectancy at local area level. Targeting the causes of death which contribute most to the life expectancy gap should have the biggest impact on reducing inequalities.

The tool provides data tables and charts showing the breakdown of the life expectancy gap in 2015-17 for two comparisons:

  1. England - The gap between each local authority/region as a whole and England as a whole.
  2. Within area - The gap between the most deprived quintile of each area (local authority/region/England) and the least deprived quintile of the area.

How to use the tool

Use the tabs at the top of the screen to move between pages of the tool.

Context page

The context page provides information on life expectancy and life expectancy gaps. This can be used as a guide to which comparison(s) to select on the Breakdowns page.

Select a geography type and geography from the dropdown box.

Two tables are then displayed. The first shows life expectancy in the selected geography, in England as a whole, and the absolute gap in life expectancy between the two. The second shows life expectancy in the most deprived and least deprived quintiles of the selected geography, and the absolute gap between the two.

Breakdowns page

The breakdowns page provides information on the causes of death and age groups which are driving the gaps in life expectancy, either within the selected geography, or between the selected geography and England.

Select from the dropdown boxes to display data and charts of interest:

  • Geography type and geography - select a geography type and geography from the dropdown box.

  • Comparator area - select ‘England’ to view the breakdown of the gap between the selected geography as a whole and England as a whole, or ‘Within area’ to view the breakdown of the gap between the most and least deprived quintile of the selected geography. The England comparator is likely to be most useful to areas where the life expectancy is lower than England, however, areas with a lower life expectancy than England should also consider within area inequalities. Scarf charts are not available where life expectancy of an area is higher than England, however, bar chart data are available for all areas, since even in areas with a higher life expectancy than England, there may be specific causes of death which are causing a reduction in life expectancy which could be targeted locally.

  • Segment gap by - select to view breakdowns by either cause of death or age group.

  • Chart type - select the chart type of interest.


Move between viewing charts and data tables using the tabs.

Interpreting the outputs

Three types of chart are available in the tool: scarf charts, broad bar charts, and detailed bar charts. A data table corresponding to each chart is also available.

The scarf charts show the percentage contribution that each broad cause of death, or each broad age group, makes to the overall life expectancy gap between the areas selected. For the England comparison (local authority/region as a whole to England as a whole), scarf charts are only available for areas where the life expectancy in the local authority/region is lower than the life expectancy in England. For the within area comparison, scarf charts are only available for areas where the life expectancy in the most deprived quintile is lower than life expectancy in the least deprived quintile. If a cause of death or age group is not displayed in the chart (or percentage contribution shows as “-” in the data table), this means that the cause of death or age group does not make any contribution to the life expectancy gap.

The broad bar charts show the amount that life expectancy would increase (in years) in the selected local authority/region (or the most deprived quintile of the selected area) if its mortality rate for each age group or cause of death was changed to that of the comparator area, assuming all other rates remained constant. Contributions that widen the inequality gap (that is, where mortality rate is higher in the selected area than the comparator area) are represented with a positive value. Contributions that offset the gap (that is, where mortality rate is lower in the selected area than the comparator area) are represented with a negative value.

The detailed bar charts show the same information as the broad bar charts, but for a more detailed list of causes of death.

In addition to the data displayed in the charts, the data tables show the number of deaths occurring in the selected area (England comparison), or most deprived quintile of the selected area (within area comparison), for each cause of death or age group. Alongside this, the number of excess deaths are displayed. Excess deaths are the number of ‘extra’ deaths that occur in the selected area (England comparison), or most deprived quintile of the selected area (within area comparison), because it has a higher mortality rate for that cause of death than the comparator area. If these deaths were prevented, then the contribution of that cause of death to the overall life expectancy gap would be eliminated.

Further information on interpreting the outputs can be found in the guidance and FAQs tab.

Comparability with previous versions of the Segment Tool

This version of the Segment Tool is not directly comparable with the previous versions. This is due to a change in the methodology being used to calculate the breakdowns of life expectancy implemented in this version of the tool.

Guidance and FAQs

More detailed guidance on interpreting the results is available on the guidance and FAQs tab. This includes information on the data and methods used to construct the tool. A set of frequently asked questions is also available.


This tool was last updated on 22nd May 2019

Contextual information

Contextual information

Download data (.csv)



Breakdown of the life expectancy gap

Breakdown of the life expectancy gap

Download chart (.png)

Download data (.csv)
Download technical guidance (.pdf) Guidance and frequently asked questions

Guidance and frequently asked questions

Background

The Segment Tool provides information on the causes of death and age groups that are driving inequalities in life expectancy at local area level. Targeting the causes of death which contribute most to the life expectancy gap should have the biggest impact on reducing inequalities.

The tool provides data tables and charts showing the breakdown of the life expectancy gap in 2015-17 for two comparisons:

  1. England. The gap between each local authority/region as a whole and England as a whole. This option is only available if the local authority/region selected has a lower life expectancy than England.
  2. Within area. The gap between the most deprived quintile of each area (local authority/region/England) and the least deprived quintile of the area. This option is only available if the most deprived quintile has a lower life expectancy than the least deprived quintile.

The Segment Tool was first published in January 2014, and most recently updated in May 2019. The latest update incorporates a number of changes including:

  • Providing the tool as an interactive web tool (using Rshiny), replacing the previous Excel tool and pdf reports
  • An update of data to 2015-17
  • A revised methodology to calculate the contributions of causes of death to life expectancy gaps
  • Inclusion of the contribution of specific age groups to life expectancy gaps, in addition to causes of death
  • Revision of the cause of death groups included in the tool

Due to these changes, the results in this version of the Segment Tool are not comparable with previous versions.

Data

Deaths

Numbers of deaths are based on Office for National Statistics (ONS) death registration data. Deaths were extracted for the relevant geographies for years 2015, 2016 and 2017 and pooled.

Cause groups have been defined using International Classification of Diseases, Tenth Revision (ICD-10) codes and the groupings used are specified in the table below. Broad causes of death are consistent with those used in previous versions of the Segment Tool and are based on ICD-10 chapters. Detailed causes of death include the top 10 leading causes of death (in 2016) for males and females. In addition to the 10 leading causes, the External cause group has been further broken down to include groups for land transport accidents, accidental poisoning, and suicide, as these causes of death make up a considerable proportion of deaths amongst younger adults.


Table 1: Causes of death and ICD-10 codes used in the tool

Broad cause ICD 10 code Detailed cause ICD10 code
Circulatory I00-I99 Heart disease I20-I25
Stroke I60-I69
Other circulatory Rest of I00-I99
Cancer C00-C97 Lung cancer C33-C34
Prostate cancer C61
Colorectal cancer C18-C21
Leukaemia & lymphoma C81-C96
Breast cancer C50
Other cancer Rest of C00-C97
Mental and behavioural F00-F99, G30 Dementia and Alzheimer’s disease F01, F03, G30
Other mental and behavioural Rest of F00-F99
Respiratory J00-J99 Chronic lower respiratory diseases J40-J47
Influenza and pneumonia J09-J18
Other respiratory Rest of J00-J99
Digestive K00-K93 Cirrhosis and other diseases of liver K70-K76
Other digestive Rest of K00-K93
External causes V00-Y98 Land transport accidents V01-V89
Accidental poisoning X40-X49
Suicide and injury of undetermined intent X60-X84 (age 10+), Y10-Y34 (age 15+)
Other external causes Rest of V00-Y98
Under 28 days No code assigned Under 28 days No code assigned
Other All other codes Urinary disease N00-N39
Other All other codes

Population

For the breakdown of the gap between a local authority/region as a whole and England, ONS mid-year estimates for local authorities for the years 2015, 2016 and 2017 were pooled.

For the breakdown of the gap between the most deprived quintile and the least deprived quintile in each area, ONS mid-year estimates for LSOAs for the years 2015, 2016 and 2017 were aggregated to quintiles and pooled.

Areas included

The tool provides data for upper and lower tier local authorities in England, and the English regions. Data for City of London has not been included because of the small number of deaths in this area. Data for Isles of Scilly has been combined with Cornwall.

Deprivation

Index of Multiple Deprivation (IMD) 2015 scores have been used to define deprivation quintiles.

Methods

Defining quintiles

Each local authority/region/England was divided into quintiles based on Lower Super Output Area (LSOA) level IMD scores, using the standard PHE method described on this page: https://fingertips.phe.org.uk/profile/guidance

Life expectancy

Life expectancy was calculated based on quinary age bands up to a maximum of 90+ (0, 1-4, 5-9,…,85-89, 90+), using the standard PHE method. A template life expectancy calculator can be downloaded from this page: https://fingertips.phe.org.uk/profile/guidance

Contribution to the life expectancy gap

The contribution of different age bands or causes of death to the gap in life expectancy between two areas (due to differences in age or cause specific death rates) have been calculated using a method of ‘life expectancy decomposition’.

For the Segment Tool, the Arriaga III method has been used, as described by Ponnapalli [1]. The method is based on a life table divided into 5-year age groups. The contributions of each age group are then distributed into causes of death using a method described by Preston and others [2]. Contributions are distributed proportionately according to the difference in mortality between the selected areas by cause of death within each age group.

This method is consistent with the analysis published in the PHE Health Profile for England on the causes of trends and inequalities in life expectancy. It replaces the previous method used to breakdown the gap for consistency, and also because the method distributes the life expectancy gap exactly between causes and age groups, whereas the previous method resulted in some discrepancies.

Excess deaths

For each cause of death and age group, the number of expected deaths is also provided. Excess deaths are the number of ‘extra’ deaths occurring over and above those that are expected. Expected deaths are the number of deaths which would be expected to occur if the area had the same age specific mortality rate for that cause of death/age group as the comparator area.

Interpreting the results

Scarf charts

The scarf charts show, for each broad cause of death or each broad age group, the percentage contribution that it makes to the overall life expectancy gap between the areas selected. For the England comparison (local authority/region as a whole to England as a whole), scarf charts are only available for areas where the life expectancy in the local authority/region is lower than the life expectancy in England (ie where there is a gap to segment). For the within area comparison, scarf charts are only available for areas where the life expectancy in the most deprived quintile is lower than life expectancy in the least deprived quintile.

Causes of death/age groups are only included in the scarf chart if they make a contribution to the gap in life expectancy (ie. where the mortality rate is higher for that cause of death or age group in the selected area compared to the comparator area). If a cause of death or age group is not displayed in the chart (or percentage contribution shows as “-” in the data table), this means that the cause of death or age group does not make any contribution to the life expectancy gap.

The gap in life expectancy is broken down so that the percentage contribution of causes will sum to 100 per cent. In some areas, particularly where the gap in life expectancy is small, or where only a few causes of death or age groups have excess mortality, care should be taken in interpreting the results. Some causes of death may be highlighted as contributing a large percentage of the life expectancy gap, even though the gap itself may be small.

To aid interpretation, numbers of deaths are included in the data table. The table shows the total number of deaths in the selected area (or most deprived quintile of the selected area if the within area comparison is used) for each cause or age group in the period 2015-17, and the number of excess deaths for each cause or age group. If the mortality rate for a particular cause of death or age group is lower than the comparator area, then the number of excess deaths will be negative.

When interpreting the within area breakdown, it is also important to consider the mortality rate for each cause in the local authority/region as a whole. For example, if a local authority has a very high mortality rate for cancer, the within area breakdown may not highlight cancer as a significant contributor to the within area gap because the mortality rates are consistently high across the whole local authority. In this case, cancer would still be an issue requiring consideration in the local authority, even though it had not been highlighted in the within area analysis.

Bar charts for broad causes of death/age groups

The broad bar charts show the amount that life expectancy would increase (in years) in the selected local authority/region (or the most deprived quintile of the selected area) if its mortality rate for each age group or cause of death was changed to that of the comparator area, assuming all other rates remained constant.

Contributions that widen the inequality gap (that is, where the mortality rate is higher in the selected area than the comparator area) are represented with a positive value, while contributions that offset the gap (that is, where the mortality rate is lower in the selected area than the comparator area) are represented with a negative value.

Bar charts are available for all areas, regardless of whether life expectancy is lower in the selected area than the comparator area.

Bar charts for detailed causes of death

The analysis of broad causes of death can be used to give an indication of the drivers of inequality in the area. The broad cause data should be used as a starting point, but this analysis can mask variation between causes of death within a broad cause group. For example, the contribution of cancer to inequalities in an area may be a result of very high mortality rates from lung cancer, whereas mortality rates for other cancers may be similar to the comparator.

The detailed bar charts show the same information as the broad bar charts, and are calculated using the same methods, but for a more detailed list of causes of death.

Frequently asked questions

Will the tool be developed further?

There is potential to further develop the tool. We would welcome feedback on what development would be most useful in order to inform future work.

Can I compare these outputs to those produced in the previous version of the Segment Tool?

No, the outputs are not directly comparable because of changes to the methodology and cause of death groupings used.

What does life expectancy at birth mean?

Life expectancy at birth is an estimate of the average number of years a new-born baby would survive if he or she experienced the particular area’s age-specific mortality rates for that time period throughout his or her life. The figures in the tool therefore reflect mortality among those living in each area in 2015-17, rather than mortality among those born in each area. It is not therefore the number of years a baby born in the area in 2015-17 could actually expect to live, both because the death rates of the area are likely to change in the future and because many of those born in the area will live elsewhere for at least some part of their lives.

Why does the difference in life expectancy between the most and least deprived quintile differ from the slope index of inequality in life expectancy?

The Segment Tool breaks down the gap in life expectancy between the most deprived quintile and the least deprived quintile of each area. This gap looks at life expectancy at two extreme points within an area, without considering life expectancy between those points.

The overarching measure of inequality in life expectancy in the Public Health Outcomes Framework (PHOF), is the slope index of inequality (SII). This measures variation in life expectancy across the whole range of deprivation, rather than just considering the extreme groups. The calculation takes into account life expectancy in each deprivation decile within an area, and summarises the variation into a single number. These data are available from the PHOF data tool https://fingertips.phe.org.uk/profile/public-health-outcomes-framework

This means that the difference between the most and least deprived quintile will be different to the slope index of inequality in life expectancy.

Why is the within area comparison based on deprivation quintiles instead of deprivation deciles?

The within area comparison uses the most deprived and least deprived quintile in each area, rather than the most and least deprived decile. These larger groups are used to improve the robustness of the results by reducing the number of small numbers in each cause of death or age group category.

Why isn’t a scarf chart available for my area, or why is a scarf only displayed for one sex?

Scarf charts are only displayed when life expectancy in the selected area (or most deprived quintile of the selected area), is lower than the comparator area. In some areas, life expectancy is lower than the comparator area for one sex but not for the other. In these cases, a scarf chart will be available, but a scarf will only be shown for the sex where life expectancy is lower than the comparator area.

Why, in some cases, is a cause of death shown as making a contribution to the life expectancy gap, despite there being no (or negative) excess deaths for that cause?

In a small number of cases, the output tables in the Segment Tool show that, in some areas, for a particular cause of death, there is a positive contribution to the life expectancy gap (meaning the cause makes a contribution to the life expectancy gap), and yet there are 0 or a negative number of excess deaths associated with that cause.

The number of excess deaths provided in the tables is a summary for all ages within the selected area for a given cause. However, although the area may have no excess deaths overall, the life expectancy calculation takes into account the age at which deaths occur.

Therefore, if deaths for that cause of death occur at younger ages in the selected area compared to the comparator area, this will have a greater impact on life expectancy, and therefore the life expectancy gap.

Where can I access other sources of data and information on health inequalities?

Public Health Outcomes Framework data tool: https://fingertips.phe.org.uk/profile/public-health-outcomes-framework
Health inequality tools (including the Health Inequality Dashboard): https://fingertips.phe.org.uk/profile/inequality-tools
Health Profile for England: https://www.gov.uk/government/publications/health-profile-for-england-2018
Health Equity report: https://www.gov.uk/government/publications/health-equity-in-england
Health Equity collection: https://www.gov.uk/government/collections/health-equity

References

[1] Ponnapalli K (2005) A comparison of different methods for decomposition of changes in expectation of life at birth and differentials in life expectancy at birth. Demographic Research 12:141 to 172.

[2] Preston S, Heuveline P, Guillot M (2000) Demography: Measuring and Modelling Population Processes. Blackwell Publishing.

Contact us

Contact us


We are happy to answer any questions you may have, and invite your feedback on the tool to help inform future development.

Please contact the Population Health Analysis team by email at: profilefeedback@phe.gov.uk