Compliance review of Northern Ireland tourism statistics

Overview

At the time of this report, the Northern Ireland Statistics and Research Agency (NISRA)’s tourism statistics relating to trips, nights and associated expenditure are published as official statistics.

The tourism statistics are a compendium of official statistics including estimates on the number of overnight trips and day visits, associated expenditure, as well as other measures of travel activity in Northern Ireland. Together, these statistics show the scale, value and trends of tourism in Northern Ireland.

We carried out a high-level review of the extent to which the statistics’ on trips, nights and associated expenditure included in the NISRA tourism statistics compendium comply with the standards of the Code of Practice for Statistics. This review considered whether OSR could reinstate these statistics as accredited official statistics and includes recommendations to NISRA for further improving the statistics.

Why we did this review

We first assessed the Northern Ireland tourism statistics in 2016. Our report set out several requirements to ensure that the statistics align with the standards of the Code. After NISRA met these requirements, we designated the statistics as National Statistics (now referred to as accredited official statistics) in 2017.

In April 2020, the accreditation for most of the Northern Ireland tourism statistics was temporarily suspended following a request from NISRA. This was due to the unavailability of Household Travel Survey (HTS) data from the Central Statistics Office (CSO), which provide an estimate of overnight trips to NI by visitors from the Republic of Ireland. The CSO resumed publication of these data in 2020. However, the COVID-19 pandemic significantly disrupted the broader collection of tourism data in Northern Ireland across 2020, 2021 and 2022. As such, NISRA requested that the suspension should remain in place. Consequently, the status for the statistics has remained suspended since 2020.This was agreed by OSR. During this time, NISRA published alternative data sources to provide indicators of NI tourism in the absence of trips, nights and associated expenditure data. NISRA also continued to publish occupancy in hotels as National Statistics (now referred to as accredited official statistics) and in small service accommodation and self-catering as official statistics.

The regular publication of the Northern Ireland annual tourism statistics resumed in August 2024. NISRA requested their reaccreditation in June 2025, which is the reason for this review. As the original suspension was due to the unavailability of the CSO’s HTS data and issues with data collection throughout the COVID-19 pandemic, including the cessation of interviews conducted through the NI Passenger Survey, our review focused on the quality of the four data sources used to compile statistics on trips, nights and associated expenditure:

Northern Ireland Passenger Survey (NIPS – managed by NISRA)

Continuous Household Survey (CHS – managed by NISRA)

Inbound Tourism Passenger Survey (managed by the Central Statistics Office (CSO))

Household Travel Survey (managed by CSO).

We did not review the quality of the data sources used to estimate occupancy statistics. NISRA continues to publish occupancy in hotels as Accredited Official Statistics and other accommodation establishments as Official Statistics.

Highlighted Findings

The original reason for the suspension of the accreditation was due to the unavailability of the CSO’s Household Travel Survey (HTS) due to statistical quality concerns. The response rate had fallen from 42% in 2017 to 35% in 2018 and there was a substantial increase in the percentage incidence of trips taken in the sample which led to implausible results. Following a review in 2018, CSO made survey changes and applied a statistical adjustment to the 2018 and 2019 data to address a response bias in the proportion of people responding to the survey who had taken an overnight trip. Whilst the response rate has fallen further to 26%, CSO complete an annual quality self-assessment exercise, monitor representativeness of the sample and use weighting and calibration methods to adjust for known demographic difference and mitigate non-response bias. CSO is investigating strategies to improve response, such as improving survey design to reduce survey respondent, reviewing how respondents are contacted and modes of participation and timings of reminder letters.

On the basis of evidence from users and the quality assurance steps taken by CSO and NISRA we are content that the quality is sufficient to meet user needs. NISRA has a good understanding of who its key users are and actively engages with key stakeholders. NISRA carries out a variety of user engagement activities, including an annual user group meeting, All-Island Tourism Statistics Liaison Group meetings, and tourism industry conferences and events. The most recent user group meeting demonstrated high confidence from the tourism industry in the published statistics.

The three other primary data sources used to measure the number of overnight trips, day visits and associated expenditure are also of sufficient quality to meet their intended use. The NISRA team has strong relationships with data suppliers, including through the All-Island Tourism Liaison group, and benchmark estimates against other data sources to validate and quality assure its statistics. Weighting methods are used to account for any under-representativeness across each of the surveys. NISRA publish confidence intervals and a range of quality information to be transparent to users about the level of quality.

NISRA has re-established a consistent reporting schedule for its annual Northern Ireland tourism statistics and are clear to users that data are not directly comparable prior to 2023 due to methodological changes. The unavailability of the HTS data and issues caused by the pandemic have now been resolved. The statistical bulletin, Quality and Methodology Information (QMI), and data tables are clearly presented and well-documented. NISRA provides transparent explanations for breaks in the time series and uses accessible language and where possible confidence intervals to communicate uncertainty.

The QMI for these statistics is comprehensive. It gives a detailed account of all data sources used, with information on all key quality dimensions. There is also an Easy Read Quality and Methods document to support the use of statistics by different types of users, catering for various levels of expertise. Whilst the QMI is comprehensive, the bulletin currently lacks sufficient guidance to fully support user interpretation of statistical quality. Strengthening this aspect is important to support informed use of the data. For example, NISRA should add an explicit note to notify users that statistics are not comparable by Local Government District and enhance its communication of limitations with the occupancy statistics.

NISRA includes regional comparisons with the Republic of Ireland, Great Britain and Europe providing valuable insight for users into how Northern Ireland’s tourism sector performs in a wider context. By capturing the impact that COVID-19 had on each data source, NISRA has ensured that the statistics support more meaningful comparisons over time and that users can interpret trends with confidence.

Our judgement

Based on the findings of this review, it is our view that the Northern Ireland tourism statistics, covering trips, nights and associated expenditure, comply with the standards of Trustworthiness, Quality and Value in the Code of Practice for Statistics and should be reinstated as accredited official statistics.

NISRA has been responsive to our feedback as part of this review, making prompt improvements to the statistics. For example, it added more detail on the strengths and weaknesses of data sources used in its QMI and information about how it is trying to boost response rates for the NI Occupancy Surveys and Self-Catering Survey. The newly created ‘What’s coming?’ page also helps users to understand NISRA’s future plans and developments.

To enhance the quality and value of the statistics, we recommend that NISRA:

considers how to further improve its communication of limitations in the bulletin to help users interpret and make appropriate use of the data
rigorously monitor the quality of survey data used in the compilation of the statistics, taking proactive action to address any decline in survey response rates and consider alternative data sources as part of any continuous improvement plans to ensure the continued reliability and relevance of the tourism statistics
clearly label which statistics are accredited official statistics and which are not in the compendium.

Next steps

We expect NISRA to consider implementing our recommendations to enhance the quality and value of the statistics.