Background quality report: Northern Ireland transport statistics

Date published: 30 September 2021

The background quality report contains information on how the various European Statistical System Dimensions of Quality have been considered when producing the Northern Ireland transport statistics reports.

This report provides information on the quality of the data used to produce the official statistics: Northern Ireland Transport Statistics. It informs users about the quality of the information upon which they may be drawing conclusions and making decisions. The report is structured around the five quality dimensions for statistical outputs (from the European Statistics Code of Practice). The UK Statistics Authority’s Code of Practice for Statistics requires that:

Q3.3 The quality of the statistics and data, including their accuracy and reliability, coherence and comparability, and timeliness and punctuality, should be monitored and reported regularly.


Context for the quality report.

Analysis, Statistics and Research Branch (ASRB), a Northern Ireland Statistics and Research Agency (NISRA) branch within the Department for Infrastructure (DfI) is responsible for the compilation and publication of the ‘Northern Ireland Transport Statistics’ report.

Each year, to inform this publication ASRB collate administrative data from within DfI and from Translink. After validating the data, ASRB produce and publish the report around the end of September/October. Reports are published on the DfI website. Information about the background to the publication, the quality of the data contained in it and definitions of terms are included in the report.

The first annual NI Transport Statistics publication was produced in the 1990s. It brought together in one publication a variety of useful transport information published by a number of different sources and was modelled on corresponding transport publications in the UK.

Historically, the publication has included information on vehicle registrations, driver and vehicle testing, the road network, freight, road safety, public transport, air transport, transport and disability (since 2013-14) and other transport statistics. However, following a user consultation at the start of 2018, which proposed complete withdrawal of the publication, it was reduced to include information on the road network, public transport and accessible transport only. For further information on the user consultation see the DfI website.

The outcome of this consultation resulted in the current report comprising mainly management information along with some National Statistics from the Travel Survey NI. In light of this and in line with the Code of Practice for Statistics, further user engagement was carried out in June/July 2021 to ensure the report continued to meet user needs. As a result of the findings from this recent user engagement, a decision has been taken to cease this report in its current format. User needs will be met through the development and publication of a new official statistics report on public transport; a Quality Assurance of Administrative Data (QAAD) report will be produced alongside this new report. Further information on the outcome of the user engagement can be found on the DfI website.


The degree to which the statistical product meets user needs in both coverage and content.

In line with the ASRB User Engagement Strategy, statisticians ensure that this publication remains relevant through user engagement and meetings with key users. The content of the publication has therefore changed over time, particularly after the user consultation held at the start of 2018; the outcome of the user consultation has been published alongside the publication series on the DfI website.

The latest edition of the report contains information on the road network, public transport and accessible transport. It has been continuously adapted over the years to keep it relevant, for example, the addition and removal of data tables and the inclusion of statistics on the recently introduced Belfast Rapid Transit - Glider vehicles.

As a result of these ongoing changes, the report mainly comprises management information. In light of this, user engagement has recently been carried out to ensure the report continues to meet user needs and is in line with the Code of Practice for Statistics. As a result of the findings from this recent user engagement, a decision has been taken to cease this report in its current format. The NI Transport Statistics 2020-2021 bulletin will therefore be the final report in this series. User needs will be met through the development and publication of a new official statistics report on public transport and a Quality Assurance of Administrative Data (QAAD) report will be produced alongside this new report. Further information on the outcome of the user engagement can be found on the DfI website.

The publication has been used by a wide variety of users for a range of purposes including policy development/review and monitoring and benchmarking. DfI uses the information to inform policy, set objectives and monitor performance in relation to transport in Northern Ireland. The Public Transport Division within DfI have now indicated that there is a need for official statistics on public transport to support the transparent and robust monitoring of the new Public Service Agreement with Translink and to facilitate evidence based decision making. Work will therefore now progress on the development of official statistics from Translink data for 2021-22 onwards.

Accuracy and Reliability

The proximity between an estimate and the unknown true value.

Data providers are given adequate time to provide the relevant data. Both administrative data and survey data are supplied. Data are derived from administrative systems which have full coverage and incorporate validation checks. Each provider interrogates the relevant administrative data system to populate a pre-defined MS Excel table(s) with aggregate data for onward transmission to statisticians in ASRB. Aggregate data are also sourced from the Travel Survey for Northern Ireland (TSNI), which is considered representative of the NI population. Again, these data are supplied in pre-defined MS Excel tables to ASRB. A Background Quality Report on the TSNI reports has been produced.

For all data received, variance/ logic checks are employed by statisticians as an integral part of the production process with any large discrepancies between current and previous year queried with the data provider. As part of their quality assurance processes, statisticians also analyse trends and check that values fall within acceptable ranges.

Previous data are revised if necessary and appropriate. All revisions are conducted in line with ASRB’s Revisions and Errors Policy. In line with this policy, a minor correction was included in Table 3.1 of the scheduled release of the 2020-2021 report and a correction notice was added to bring this to the attention of users.

As the report currently includes a high proportion of management information, work will now commence to produce key public transport official statistics in line with user need.

Timeliness and Punctuality

Timeliness refers to the time gap between publication and the reference period. Punctuality refers to the gap between planned and actual publication dates.

The majority of figures presented in the Northern Ireland Transport Statistics report relate to either the financial year, the position at the end of the financial year or the position at 1st April. Travel survey data presented in Chapter 3 relate to the latest three calendar year period.

The production process begins in the summer with the issue of individual data requests for each series of statistics to the relevant sources. Collection and validation of the data follows and then the data are formatted and the report published around the end of September/October.

Historically there has been a lag of six months between the end of the financial year and the publication date.

Advance notice of ASRB publication dates is available in the upcoming statistical releases calendar on the DfI website. Publication dates are also pre-announced on GOV.UK. To date, all editions of the publication have been released on time. In the event of a change to a pre-announced release date, the delay would be announced and explained on both the DfI website and GOV.UK and the new publication date specified. If necessary, updates would be given regularly. The statistical release calendar and DfI website have been updated to reflect that the NI Transport Statistics 2020-2021 report will be the final report in this series.

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.

The publication series is available to download free of charge in PDF format on the DfI website.

The statistical tables are also available to download in MS Excel format and ODS (Open Document Spreadsheet) format, from the webpage. If requested, ASRB can provide hard copies or other suitable media.

The publication is accessible through the UK Official and National Statistics Publication Hub.

User Information is included in the publication to help users to understand and make the best possible use of the data. In addition, where necessary, explanatory footnotes are included in the tables.

ASRB worked with DfI’s Graphic Design Unit to enhance presentation of the information in the statistical report and to ensure the needs of those with visual impairments were considered.

Every effort has been made to ensure that the publication complies with the AA standard under the Web Content Accessibility Guidelines (WCAG) 2.1.

The publication contains contact details of the responsible statistician who can be contacted for further information.

Coherence and Comparability

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

ASRB supply data providers with pre-defined MS Excel tables to complete. This aims to ensure consistent recording, coverage and timeframes with previous year’s figures.

Comparisons can be made over time and the latest data are always compared with previous years’ data, where appropriate, and any significant changes are thoroughly checked and validated. The public transport data published for 2020-2021 reflect the impact of the Coronavirus pandemic and the commentary and guidance have been updated to reflect that.

Trade-offs between Output Quality Components

Trade-offs are the extent to which different aspects of quality are balanced against each other.

There are not considered to be any trade-offs.

Assessment of User Needs and Perceptions

The processes for finding out about users and uses, and their views on the statistical products.

In line with the ASRB User Engagement Strategy, the content of the publication is informed by an understanding of customers’ information needs. It is with this understanding that a decision has been taken to cease the publication of the NI Transport Statistics bulletin. This conclusion is based on an assessment of user need as outlined on the DFI website.

ASRB maintain a mailing list of users who are notified by email each time a report is published. This mailing list was refreshed prior to the user engagement exercise being announced in June 2021. The email that is issued to users also asks them to let ASRB know if they no longer wish to receive this notification. Users on this distribution list were invited to complete the user engagement survey carried out in June 2021.

There is an ongoing ASRB customer satisfaction survey, which includes a question on whether ASRB publications (including NI Transport Statistics reports) meet customers’ needs. The link to the survey is issued every time users are notified that a report has been published or when an ad-hoc query is answered. Results are collated on a quarterly basis.

The data presented in the publication help to meet the needs of both internal and external users. User needs are prioritised, taking account of resources available and the feasibility of any additional needs identified. The prioritisation of user needs means that ASRB will now focus resources on the development of public transport official statistics.

Performance, Cost and Respondent Burden

The effectiveness, efficiency and economy of the statistical output.

In the production of this publication, ASRB endeavour to operate efficiently by placing the minimum load necessary on data providers.

ASRB issue pre-defined MS Excel tables for ease of completion for each series of statistics to the relevant sources. The data providers return all of the information via email. There is ongoing communication with data providers to ensure timely receipt of data.

On receipt of the information, statisticians validate data and prepare for publication. This may involve further liaison with data providers. Once data are verified, statisticians prepare for publication within a short timeframe.

Confidentiality, Transparency and Security

The procedures and policy used to ensure sound confidentiality, security and transparent practices.

All of the information required for this publication is provided in pre-defined MS Excel tables, which collect aggregate data. Personal information is not collected and statistical disclosure control methods do not need to be applied to the data.

The data are held on a secure and accredited network drive that is only accessible to ASRB staff or within DfI’s secure record management system (Content Manager), also with restricted access.

ASRB’s Data Governance and Confidentiality Statement is available on the DfI website.

Further Information

For further information relating to the quality of ‘Northern Ireland Transport Statistics’, please contact

Last updated: September 2021

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