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Outcome Indicator Framework

Table of contents

Introduction and aim

The government published the 25 Year Environment Plan in January 2018 setting out goals for improving the environment in England. A commitment was made to develop a comprehensive set of indicators to measure environmental change. These indicators help us to show how the environment is changing over time. This will support the assessment of policies and other interventions, including how we are delivering on international and domestic commitments. In particular, the Outcome Indicator Framework can support the statutory cycle of monitoring, planning and reporting on progress in improving the environment as established by the Environment Act, (2021).

The Environment Act established the 25 Year Environment Plan as government’s first Environmental Improvement Plan, which has since been updated while maintaining the same 10 overarching goals. The Outcome Indicator Framework continues to serve the needs of the 25 Year Environment Plan/Environmental Improvement Plan and a regular cycle of evidence review and indicator refinement maintains this customised policy focus.

The first Outcome Indicator Framework report: ‘Measuring environmental change: Outcome Indicator Framework for the 25 Year Environment Plan’, was published in May 2019. Drawing on advice from a wide range of experts and stakeholders, it presented 66 indicators to give a comprehensive view of the environment and how it is changing. The 2019 report set out in detail the purpose of the Outcome Indicator Framework and examples of how the indicators can be used.

The Outcome Indicator Framework has an important role in our longer-term understanding of the effectiveness of policies and interventions. The indicators are a systematic means of monitoring environmental change, recognising that complex natural and social systems will respond to change on a range of timescales.

The Outcome Indicator Framework will:

Structure

Outcome indicators are:

The 66 indicators are arranged into 10 broad themes. These are topics that people will generally recognise as relating to different aspects of the environment (for example, air, water, seas and estuaries, and wildlife). Some indicators may be applicable to one or more themes but have been allocated to just one of them. The 25 Year Environment Plan goals and targets relevant to each indicator are detailed within each of their descriptions.

The inclusion of 66 indicators in the framework provides a comprehensive and systematic means to observe and convey environmental change. However, for some purposes it may not be necessary to examine this large number of indicators. Therefore, in the framework we identify a sub-set of the indicators under 16 headlines; these are highlighted in the individual indicator pages of this dashboard. The headline indicators relate to key aspects of the environment which are a focus of policy intervention and should make intuitive sense to a wide range of readers. When complete, the framework will present a large amount of information and so we will highlight key indicators under headlines to provide a way to simplify this information and provide clear communication.

Further examples on how the headlines and indicators may be used are given in Section B of the 2019 Outcome Indicator Framework report.

Using the framework

The Outcome Indicator Framework is designed to be adaptable for multiple uses. For example, it can be used to communicate environmental change or to support management of natural capital. By presenting a wide variety of data in a single location, the framework enables a comprehensive approach to analysis of environmental issues and decision making.

The concept of natural capital was used to develop the framework. Natural capital is defined as the elements of the environment which provide valuable goods and services to people such as clean air, clean water, food, and recreation. A natural capital approach is advocated by the 25 Year Environment Plan/Environmental Improvement Plan as it accounts for all the different ways the environment benefits society and so can inform better decision making. A natural capital framework sets out the need to:

The 66 outcome indicators can be considered as either a measure of (a) the drivers or pressures on natural capital assets, (b) the extent or condition of natural capital assets or (c) the services or benefits associated with natural capital assets. This classification is not always straightforward since the condition of one natural capital asset (for example, air quality) may place a pressure on another (for example, wildlife habitat).

It is important to recognise that multiple interactions occur across the indicators and categories. By classifying these indicators in this way, we can also show which direction of change in the indicator reflects an improvement to the environment (that is a downward trend for pressures and an upward trend for the condition of an asset or the provision of a benefit).

This structure is flexible, and indicators can be selected as appropriate to the needs of a particular analysis; several examples of how the indicators may be used to examine specific questions are provided in our 2019 Outcome Indicator Framework report. Monitoring and evaluation of these indicators can inform appropriate actions with an ultimate goal of maximising a healthy environment, economy and society.

The indicators that can be considered drivers or pressures on natural capital assets are:

The indicators that can be considered extent or condition of natural capital assets are:

The indicators that can be considered services or benefits associated with natural capital assets are:

Latest annual update

This 2025 version of the dashboard includes data on environmental trends for 65 of the 66 outcome indicators spanning across the 10 themes in the Outcome Indicator Framework.

In this dashboard we update trends for 47 of the indicators reported in 2024, reflecting the most recent available data. Wherever appropriate, when indicators are updated the entire time series is updated to reflect methodological refinements and this can sometimes result in changes to the historic data reported in previous iterations of the dashboard. Of the indicators reported in 2024, 19 have not been updated as no new data or analysis were available for inclusion in the 2025 dashboard at the time of evaluation.

Four of the indicators presented in this 2025 update to the dashboard are classified as 'official statistics in development':

These indicators are being published at source as official statistics in development in order to facilitate user involvement in their development – information on how the data have been obtained and how the indicators have been prepared is available via the links in the individual indicator pages of this dashboard. We would welcome any feedback, particularly on the usefulness and value of these statistics, via 25YEPindicators@defra.gov.uk.

Of the 65 indicators presented, 39 are categorised as interim. Interim indicators are not inferior to final indicators in terms of quality and/or reliability; the category is used to describe those where further development is expected to extend or improve the reporting of the indicator. Reporting interim indicators means that we can communicate data where they are available, whilst recognising that further development is necessary for the indicator to be complete. Examples of circumstances under which an indicator is considered to be interim include: data need to be extracted for England from a UK wide dataset, additional data need to be added to the indicator, or the methods used for deriving an indicator are expected to be further developed. The specific reason why an indicator is currently presented as interim is described in the individual indicator pages of this dashboard. Indicators are described as ‘final’ when no further significant development is immediately expected, notwithstanding the future development of the framework as a whole.

One indicator, E7: Healthy Soils remains in development. Detail on progress made in the development of this indicator, including a link to a progress report which includes emerging findings can be found on the indicator page.

A limited number of changes have been made to the indicator descriptions over the last year. These reflect feedback as well as further consideration and development of the indicators to ensure the most appropriate data are presented. There have also been some specific changes to individual indicators after further consideration of their intended purpose, in order to better reflect alignment with 25 Year Environment Plan commitments and to deliver the insights required to support associated policy needs.

Indicator A3: Concentrations of fine particulate matter (PM2.5) in the air has been revised so as to better align with reporting against the Population Exposure Reduction Target and the Annual Mean Concentration Target for PM2.5. However, while the indicator now presents the same data as are used to assess compliance with these Environment Act targets, the assessment methodology used to formally monitor progress towards the Population Exposure Reduction Target differs from the assessments reported in the A3 indicator.

Indicator A6: Exceedance of damaging levels of nutrient nitrogen deposition on ecosystems has been revised. It now contains 2 components. A6i continues to present the percentage of sensitive habitats exceeding critical loads, and A6ii presents new data on the average accumulated exceedance of nutrient nitrogen. These new data show that although levels of nutrient-nitrogen deposition are falling, critical loads are still exceeded across almost 100% of sensitive habitats in England.

A methodological change has been made to indicator C11, including a name change to C11: Status of sensitive fish species. The underlying indicator, developed for the OSPAR convention is more aligned with UK Marine Strategy Descriptor D1: Biodiversity, as opposed to Descriptor 3: Commercial fish, or D4: Food webs. The species assessed in C11 are not commercially viable, as they are generally uncommon due to depletion or natural rarity. These methods have been produced for fish as opposed to shellfish, the status of which is better described in E9: Percentage of our seafood coming from healthy ecosystems, produced sustainably, H4: Exposure and adverse effects of chemicals on wildlife in the environment and a measure of shellfish sustainability will be included in C10: Productive seas: fish and shellfish stocks fished sustainably, following the UK Marine Strategy Part One update in 2025. Indicator G4: Engagement with the natural environment has been revised. It continues to present data for adults and children from Natural England’s People and Nature Surveys, but historic data from the Monitor of Engagement with the Natural Environment survey are no longer included in the G4 indicator because they cannot be compared with the more recent People and Nature Survey results. Two additional metrics have also been added to this indicator that report on (i) the proportion of adults visiting green and natural spaces in the past 14 days, and (ii) the gross annual number of adult visits to green and natural spaces.

A methodological change has been made to indicator H5: Exposure to transport noise, introducing new metrics to the indicator. The publication of the Defra’s new strategic noise maps the indicator now provides insight into the percentage of the population exposed to transport noise disaggregated to road, rail and aircraft noise, these are available for reporting across day-evening-night weighted across a 24-hour period and for nighttime noise.

Additional persistent organic pollutants (POPs) have been added to J5: Prevent harmful chemicals from being recycled, including data on the stockpile of brominated chemicals hexabromocyclododecande (HBCDD) & decabromodiphenyl ether (DecaBDE). Metrics showing incineration rates for HBCDD and DecaBDE have also been added.

Indicator K4: Extent and condition of terrestrial and marine protected areas in the UK Overseas Territories (UKOTs) has been revised to better track trends over time. The indicator has been revised to track changes in the percentage of the total marine and terrestrial protected areas and other effective conservation methods across all UKOTs. Additionally, the indicator now includes a breakdown of the percentage of protected areas for each individual UKOT.

Assessment

A new assessment section was added for the first time to the 2022 update of the Outcome Indicator Framework report and dashboard, to help with interpreting results, to allow for easier comparison across indicators and to enable the production of additional summary statistics. This section has been updated in the 2025 version of the dashboard for indicators where new data were available. The assessment methodology has also been updated in the 2025 version of the dashboard. These changes are outlined in the assessment section, but in summary, the final smoothed data point is no longer excluded from assessment calculations, which serves to lessen the data lag impacting progress reporting of the 25 Year Environment Plan/Environmental Improvement Plan.

Consistent categories of change for different time periods have been assigned to all indicators which are already published in a suitable format and with sufficient historic data to enable analysis. Indicator-specific results with a supporting narrative are provided for each indicator within the relevant indicator specific pages of this dashboard.

Where data are available for individual indicators, an assessment of environmental change since 2018 has been undertaken, to reflect progress made since the publication of the 25 Year Environment Plan/Environmental Improvement Plan. However, it is important to note that for most indicators, the currently available time series of data points since 2018 does not yet allow for anything more than an early indication of likely change. It is expected that the ongoing annual updates of the Outcome Indicator Framework will in time allow for statistically robust assessment of changes since 2018. This will require more than 5 data points in a given indicator’s time series since 2018 to minimise the impact of year-to-year fluctuations which make it difficult to interpret a clear trend. For this reason, care should be taken to not overinterpret offered assessments for the ‘since 2018’ category, as this is not felt to be as robust an assessment as the other categories which have more datapoints informing their analysis. It is also important to note that time lags exist in the environmental responses to interventions. It is expected that the majority of outcome indicators will require longer-term reporting (greater than 5 years) before they may be considered as showing response to policy and other actions.

There are important considerations to be aware of when interpreting results. These are highlighted in the assessment background section of this dashboard, a new addition which also provides more detail on the aims of the assessment and the methodology employed. The assessment results section presents summaries of assessment results by each 25 Year Environment Plan Goal. These summaries help to interpret how much change has been observed across goals and include information on potential links between indicators for different goals to indicate where there may be knock on effects.

Future development

Currently, some indicators are not yet available to report their full intended scope, and further research is required to determine the most suitable data and methods for analysis. We expect additional indicator data to be reported in future updates.

The technologies for monitoring and assessing change in the environment are advancing rapidly and offer new cost-effective methods (for example, Earth Observations, DNA methods, citizen science / mobile apps and new sensor technologies). We will look to update indicators to reflect these developments when appropriate but will ensure the environmental parameters used for reporting indicators are consistent and so retain the trend time-series where possible.

The Outcome Indicator Framework will be kept under regular review so that it continues to be relevant and provide the best and most cost-effective ways of assessing progress. An updated Environmental Improvement Plan (EIP25) is expected to be published as an update to the 25 Year Environment Plan in 2025. The Outcome Indicator Framework was custom-designed to describe environmental change as relevant to the 10 overarching goals of government’s inaugural 25 Year Environment Plan. EIP25 constitutes a refreshed update to the 2023 Environmental Improvement Plan and the continuation of the original 10 goals means the Outcome Indicator Framework remains an authoritative depiction of how the environment is changing in this context. The Outcome Indicator Framework has always been intended to remain dynamic to best capitalise on new data opportunities and will be regularly reviewed for optimisation, which will also consider ongoing alignment with new fine-grain EIP25 policy detail and statutory environment act targets.

Further research into new potential assessment approaches is ongoing to build on the initial assessment of change analyses introduced in 2022. This work will consider appropriate statistical techniques and timeframes, and in future years, it may focus on the indicator headlines and their corresponding indicators. Where possible, a baseline near to 2018 (to align with the publication of the 25 Year Environment Plan) will be used as a reference point to assess change. Longer-term (historic) trends will also be presented for comparison where these data are available. Where suitable time-series are available, we will also assess medium-term and short-term trends.