Accredited official statistics

Search and rescue helicopter statistics: Background quality report

Published 18 June 2024

This background quality report relates to the publication of quarterly and annual data from civilian search and rescue helicopter (SARH) operations in the UK.

The purpose of this document is to provide users of the statistics with information about the quality of the outputs, measured against different dimensions of statistical quality.

As a result, this document helps to demonstrate how the department complies with the Code of Practice for Statistics principle on quality.

These statistics are designated as accredited official statistics. Accredited statistics are produced to high professional standards as set out in the Code of Practice for Statistics. They undergo regular quality assurance to ensure they meet customer needs.

Code of Practice for Statistics

The Code of Practice sets out common standards that should be followed by all UK organisations that produce official Code of Practice statistics.

Section 1: Background to the statistics

Search and rescue helicopters are on standby 24 hours a day to assist those in difficulty, both at sea and over land, as part of a wider search and rescue provision which includes maritime and land based operations. These statistics are collected to provide information on the number and type of SARH taskings.

From April 2015, the mix of military and civilian search and rescue capacity, managed by the Ministry of Defence (MOD), began to transition to a single civilian contract. This is now managed by the Maritime and Coastguard Agency (MCA), with statistics on search and rescue helicopters (SARH) reported by the Department for Transport (DfT).

A completely separate statistical series has now been established by DfT, covering the civilian bases, from the point at which they opened. As part of the transition to the civilian contract, 2 new SARH bases were opened in April 2015, 2 in July 2015, 1 in October 2015 and two more in January 2016. Since July 2017, all SARH bases have been fully operational across the United Kingdom. The Portland base ceased operation after June 2017. Data is available for this base from its initial operation in April 2015 to its last operation in June 2017.

Map 1: Map of UK SARH bases

Map 1 shows the location of UK SARH civilian bases and whether they are currently open or closed. These are:

• Sumburgh, opened in April 2017
• Inverness, opened in April 2015
• Humberside, opened in April 2015
• Lydd, opened in August 2015
• Lee-on-Solent, opened in April 2017
• Portland, closed in June 2017
• Newquay, opened in January 2016
• St Athan, opened in October 2015
• Caernarfon, opened in July 2015
• Prestwick, opened in January 2016
• Stornoway, opened in July 2017

Methodology and Production

Between April 2015 and June 2017, data used to produce these statistics was derived from an administrative system used by the helicopter operators (known as iSAR) and provided to DfT by the Maritime and Coastguard Agency. From June 2017, the statistics are based on information recorded by the Aeronautical Rescue Co-ordination Centre (ARCC) based in Fareham. ARCC are responsible for the co-ordination of the search and rescue helicopters, from answering the initial request through to the conclusion of the tasking.

These statistics are based on administrative data, with the process broadly as follows.

Step 1

Following a tasking, the ARCC operator handling the incident records data into a single spreadsheet. Checks are put in place to make sure the data inputs are accurate and reliable. Operators follow guidance from MCA and DfT around the definitions of variables where an interpretation is needed (such as, when the variable is not captured on the system) - in order to categorise the type of tasking (search, support, rescue or recovery and pre-arranged transfer). An ARCC Supervisor would then check the recorded data to ensure variables are categorized accurately and consistently by different operators, as far as is possible in the operational environment.

Step 2

 This spreadsheet is sent to the MCA and DfT on a monthly basis, with MCA checking the incidents captured are correct for contractual purposes.

Step 3

DfT validates the data to verify that the data items are accurate and consistent. This includes:

• cross checking the details against those entered in the helicopter operator system (iSAR)

• checking for missing data and any anomalies

• checking that the location type and type of tasking matches with the tasking narrative

• checking that the location of the tasking is not too far from the base, and matches the tasking narrative

These checks are done using a validation dashboard created in R (a statistical programming software).

Step 4

 Any anomalies and amendments are sent back to the MCA for verification. DfT then signs off the monthly data for use in production of the statistics.

Step 5

 Once the data is finalised, it is entered into a SQL database, where data tables are exported to R and the tables and statistical release are produced for publication.

Step 6

Each statistical release produced is independently checked by a statistician where any discrepancies are resolved before being approved by the senior statistician.

The department has reviewed the frequency of the search and rescue helicopter statistical series and has reduced it from two publications a year to one annual release in the summer (June). The last biannual statistics release was for April to September 2022.

Section 2: Quality assessment

In this section, the quality of the statistics is considered in relation to the different dimensions of quality as stated in the European Statistical System (ESS) quality framework.

European Statistical System (ESS) quality framework:

The European Statistical System (ESS) handbook for quality reports provides comprehensive guidance on measuring the quality of statistical processes.

  1. Relevance

Relevance is the degree to which a statistical product meets user needs in terms of content and coverage.

The statistical outputs presented within SARH statistics include:

• a statistical release containing key findings, trends over time and signposts to further information

• Open Document Spreadsheets (ODS) data tables containing information on the number of SARH taskings, location, and individual level information

• an interactive dashboard highlighting each tasking in greater detail for the annual statistics

• a document outlining the changes in data sources after April 2017.

Known users and uses of the statistics

Within the DfT and MCA, the statistics are used:

• for ministerial briefing and to answer public enquiries
• as background to policy development
• for monitoring trends in search and rescue activity
• by analysts in modelling overall search and rescue operations.

Outside of DfT, known users include:

• search and rescue partners, national parks, tourist boards, mountaineering groups and others monitoring the use of search and rescue services
• air ambulance charities monitoring SAR activity in their areas
• maritime organisations monitoring SAR activity related to their businesses (for example, near ports).

How well the statistics meet user needs

DfT published the first quarterly SARH statistical release in November 2015 and alongside this, launched an online survey asking users for feedback on the statistical release, which ran until January 2016. A summary of the user response was published and provide information on the extent to which user needs are being met, and where user feedback has been addressed such as incorporating new analysis within the statistical reports.

Since the introduction of the first SARH statistics publication, DfT have made a number of changes to better meet user needs. These include:

• changes in data source to ARCC has enabled DfT to produce new analysis such as the number of people rescued in a helicopter
• an interactive dashboard containing individual level taskings to cater to users wanting specific information about a certain base or region
• additional analyses including taskings by day of week, region, and a breakdown of location type.

2018 user survey and response

Another user survey was carried out in March 2018 and the results are published on the guidance page. As part of this survey, the department proposed to discontinue a number of tables, as they receive minimal user interest. This would not result in any loss of data as all of the data from these tables would be incorporated into the existing SARH0112 (record level data table).

It was also proposed to change the frequency of the release, which would see two reporting periods per year rather than four, reflecting a summer and winter trend.

Following the survey, these changes came into effect with the annual statistics for the year ending March 2019, published in June 2019.

The department has reviewed the frequency of the search and rescue helicopter statistical series and has reduced it from two publications a year to one annual release in the summer. The last biannual statistics release was for April to September 2022.

User feedback

DfT further developed the statistical outputs in response to user feedback. The table below provides a summary of user requests received, and the outcome.

User requests	Outcome
Enhance outputs, including better information at an individual base level.	Published the first interactive mapping document in June 2017, later enhanced the dissemination by producing an interactive dashboard (from December 2017 onwards).
Estimates of the number of people rescued.	Changing data source in August 2017 allowed us to include statistics on number of people rescued and assisted.
A more thorough breakdown of the type of taskings which occurred.	The new data source also allowed us to include a breakdown of the type of taskings (for example, whether the tasking was a mountain rescue, vessel in difficulty).
More information about the precise details of each incident.	We now publish a record level table (SARH0112) which includes the different variables of interest.
Statistics about the durations of taskings, by type (for example - search, rescue or recovery).	This information is now available for all taskings in the record level table (SARH0112).
Details of the primary responder (for example, police force, air ambulance).	Pending – something we may include in the future releases if there still are user interests, and subject to data quality being sufficiently good.
Statistics about response times – from the initial contact phone call to the helicopter taking off.	Pending – something we may include in the future releases if there still are user interests, and subject to data quality being sufficiently good.
Information about the cost of SARHs.	Something we will not be able to include in the release as we do not have access to the cost data and it is commercially sensitive.
Information on downstream outcomes (for example whether lives are saved when casualties are transferred to medical centres and whether there are any fatalities).	Something we will not be able to include in the release as the data on this is not available.

2. Accuracy and reliability

Accuracy refers to how close the estimated value in the output is to the true result.

The following table summarises potential sources of risks or errors which may arise throughout the process of compiling the SARH statistics.

Potential source of error	Risk of error mitigation
Taskings missed, or wrongly included by ARCC	As all SARH emergency calls are received by the ARCC and recorded into a spreadsheet, missing records are unlikely. In addition, taskings recorded are validated by MCA for contractual purposes and the data is compared with the iSAR system and checked by MCA. This ensures that any out of scope taskings are also identified.
Missing or inconsistent data items in the spreadsheet	Inconsistent data or missing variables information are queried by DfT and MCA. Where discrepancies are identified in relation to the classification of a tasking, the description of the tasking entered in the iSAR system is used to resolve them.
Production of statistical publication and data tables	Tabulations and basic checks are also performed on the SARH data to make sure they are in line with expectation (for example, we would expect SARH taskings to peak in the summer months in a given year due to greater leisure activity). The data are also checked with previous years, looking for any unexpected changes for each variable. Where uncertainties exist in data outputs, these are highlighted in the statistical releases.

DfT have a close working relationship with the MCA and the ARCC to ensure the quality of the data is maintained. The team at the ARCC are trained in recording incidents and guidance is supplied to those who are responsible for inputting data in order to ensure that this is as consistent as possible.

Because of the thorough data validation process undertaken by DfT every month, it is rare for the SARH statistics to be revised.

  3. Timeliness and punctuality

Timeliness describes the time between the date of publication and the date to which the data refers, and punctuality describes the time between the actual publication and the planned publication of a statistic.

SARH statistics are currently published annually, with tables and a report included in the annual publication. The production of these report and the tables commences after the final month’s data for the required 12 months is received. The publication date for this statistical release is agreed at least 1 month in advance and the date is published on the GOV.UK release calendar.

To date, all SARH statistical releases have been published to the scheduled pre-announced date.

We aim to publish the release 3 months after the end of the period to which the statistics relate to, so the annual release is published around June.

The department has reviewed the frequency of the search and rescue helicopter statistical series and has reduced it from two publications a year to one annual release in the summer. The last biannual statistics release was for April to September 2022.

  4. Accessibility and clarity

Accessibility is the ease with which users are able to access the data, also reflecting the format in which the data are available and the availability of supporting information. Clarity refers to the quality and sufficiency of the metadata, illustrations and accompanying advice.

Accessibility

The outputs are published on the GOV.UK DfT statistics page in accessible formats.

Statistical releases and are available as html files, which are accessible for those who use assistive technologies.

Data tables are available in ODS file format which can be accessed by using freely available software. The spreadsheets have been designed to be used easily by assistive technologies.

Individual level raw data tables and an interactive dashboard are also available for users interested in record level data on taskings.

Clarity

The statistical releases use plain language, in which technical terms, acronyms and definitions are defined where appropriate. The main findings are presented using a series of text, charts and maps, with maps used to show the distribution of SARH tasking locations. Full details of the strengths and weaknesses of the data are provided at the end of each statistical report for users who are interested in this.

In addition to the statistical releases, further relevant supporting documentation includes a note outlining the changes in data sources from April 2017.

  5. Coherence and comparability

Comparability is the degree to which data can be compared over time and domain. Coherence is the degree to which data that are derived from different sources or methods, but refer to the same topic, are similar.

Comparability

Over time

The statistical releases cover trends since April 2015, the first period for which data are published by DfT. Over this period, the number of civilian bases grew from April 2015 onwards. The final two bases (Prestwick and Newquay) began to fully operate from January 2016 onwards. Trends over time, across all bases, can only be made in a comparable way from this point.

In addition, the transition of data sources from iSAR to ARCC took place in June 2017. DfT compared data from the two sources where this was possible (for the first 3 months of 2017) which showed a close correspondence between the two sources; consequently the change of source is not considered to have impacted the trends shown in the statistics.

By base

The Portland base only operated a 12 hour service compared to the other bases that operates 24 hours a day. Therefore, this should be taken into account when interpreting the results.

Previous UK SARH statistics

Historically, the MOD produced monthly, quarterly and annual statistics releases covering search and rescue helicopters. The statistics covering the military operations were badged as accredited statistics and provided in-depth coverage, whereas the statistics for the civilian operations were much more limited and were not badged as accredited statistics (they covered a brief summary table at the end of the publication). The DfT statistics series as of 13 June 2018 are now designated as accredited statistics.

During the transition period, the MOD continued to produce quarterly and annual statistical publications as usual, for those bases that remained open, until they ceased operations. The last MOD base closed on 31 December 2015, and the final statistics were published in February 2016. Although similar, as the two sets of figures were collected in from different sources, comparisons between them are not made.

Coherence

The statistical publication reports on all SARH activity in the United Kingdom, including the Channel Islands, Isle of Wight and Isles of Scilly.

The Irish Coastguard is responsible for all search and rescue helicopter activity in Ireland, but do not publish official statistics in a comparable format; some information on the number of Irish helicopter taskings is available as part of the Coastguard end of year statement.

Due to the various different methods used for reporting search and rescue activity in different countries, it is not possible to directly compare the UK SARH statistics to others internationally.

DfT intend to explore data from other search and rescue organisations such as lifeboats and coastal rescue teams, and whether it is possible to expand the coverage of these statistics to cover wider UK Search and Rescue statistics in the future.

6. Trade-offs between output quality components

Trade offs between output quality components describes the extent to which different aspects of quality are balanced against each other.

The main trade-off is accuracy against timeliness and respondent burden. DfT have a documented process to follow from receiving the data from suppliers, cross checking results with iSAR to internal checks and queries. Since the transition to the new data source took place, around 15% of the data was queried to the MCA and ARCC in the first 3 months of data received, with additional queries resolved internally within the DfT statistics team (for example, using the iSAR system to fill in missing data, such as incident co-ordinates).

The impact of this trade-off is reduced timeliness, in return for ensuring accuracy. If none of the data validation queries were undertaken, the statistics could potentially be published around a month earlier, but would be likely to contain less accurate data.

  7. Assessment of user needs and perceptions

Assessment of user needs and perception covers the processes for finding out about users and uses, and their views on the statistical products.

DfT regularly engages with users by social media, email and face to face methods when possible. This includes requesting feedback on the statistics series, with contact details provided in every statistical release. Each publication is promoted via DfTstats. DfT is also in regular contact with the MCA who are responsible for SARH operations, to ensure that their needs continue to be met by the published statistics.

An in-depth user consultation was carried out alongside the initial publication of the statistics, between November 2015 and January 2016. This provided DfT with a good understanding of user interests which led to the development of new dissemination techniques (including an interactive map) and publication of additional information. A further user consultation was carried out in March 2018 to assess if the SARH statistics were meeting user needs and whether further improvements could be made. The summary of the user survey can be found on the guidance page.

DfT also regularly analyses web page usage, ad-hoc requests and social media analytics to monitor activity overtime.

In line with the Code of Practice for Statistics, users will be informed about any changes or revisions to the data series.

8. Performance, Cost and Respondent Burden

Performance, cost and respondent burden describes the effectiveness, efficiency and economy of the statistical output.

The outputs are produced from the administrative data, managed by the MCA. The ARCC data is reviewed by both the MCA and DfT on a monthly basis where validations and checks are in place to ensure the correct number of taskings are recorded. Previous discussions between ARCC, DfT and MCA have resulted in more consistent recording and a set of trusted statistics that are produced to inform policy and decision making.

There is considered to be a minimal burden associated with the data supplied by the ARCC and validated by MCA, since the data is also collected for their internal purposes.

9. Confidentiality, Transparency and Security

Confidentiality, transparency and security refers to the procedures and policy used to ensure sound confidentiality, security and transparent practices.

All data is stored, accessed and analysed using MCA and DfT secure IT systems. Data protection regulations are adhered to throughout the SARH statistics production process, and any information provided to DfT by MCA and ARCC will be kept securely where access to data is controlled in accordance with departmental policy.

The information used to compile these statistics provides details on individual events (for example a brief description of the circumstances of an incident, including details such as the age and gender of those involved), though sensitive personal or identifiable personal data is not sent to DfT. The published statistics do not therefore reveal any private information about any individual or organisation. No statistical disclosure control methods are applied to the outputs, as the variables included in the statistics are not considered to be sensitive.

DfT aims to publish as much data as is possible whilst ensuring that confidentiality is maintained. In line with this, a spreadsheet of record level data containing high level variables for each tasking is published (Table SARH0112).

DfT adheres to the principles and protocols laid out in the Code of Practice for Statistics and comply with pre-release access arrangements. The pre-release access lists are available on the DfT website.

Section 3: Summary and conclusions

This background quality report presents information for users of the search and rescue helicopter statistics covering different aspects of their quality. The department concludes, on the basis of the assessment outline above, that the statistics are of a quality which is considered fit for the purposes for which the statistics are being used.

Comments and feedback on this report, or any other aspect of these statistics are welcome, and can be provided by email to search and rescue helicopter statistics.

Further information about these statistics is available, including:

• search and rescue helicopter statistics: data tables and maps

• search and rescue helicopter statistics: interactive dashboard

• search and rescue helicopter statistics: notes and definitions

• search and rescue helicopter statistics: guidance and quality information

• search and rescue helicopter statistics: user survey

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