Census 2021 data collection
Census 2021 was conducted during the coronavirus (COVID-19) pandemic, a period that caused significant changes to how people lived, worked, studied, and moved at the time.
Despite the significant challenges posed by the COVID-19 pandemic, and the need to modify some of the original plans, the Census 2021 collection was a remarkable success, achieving an overall return rate of 97.2%. This compared very favourably to Census 2011, when the return rate was 93.6%.
Details of the Census 2021 operation process can be found in the Census 2021 operational report.
Census 2021 outputs
Census 2021 successfully collected all the planned information on the population of Northern Ireland on census day, 21 March 2021. However, the unprecedented circumstances of the pandemic affected how some of the particular topics included in census outputs can be compared to previous censuses and in the long term. A summary of the main areas impacted is included below:
Labour market – activity
- The COVID-19 pandemic clearly affected the local labour market.
- Responses to labour market questions may have been directly influenced; for instance, individuals on furlough may have identified as economically inactive rather than temporarily away from work as instructed in online help provided at the time.
- When developing statistical reporting on economic activity this impact was difficult to quantify. However, Census Office was confident the data offered a robust view and included analysis of trends over time.
- Additional Northern Ireland Labour Market statistics pre and post Census 2021 are available on the Labour Market Overview pages of the NISRA website.
Labour market – place of work or study and commuting methods
- The pandemic significantly impacted workplace locations, with a much higher proportion of the population working from home as many workplaces were temporarily closed.
- The percentage of people mainly working from home rose from 10.5% (2011) to 18.9% (2021).
- A pandemic impact can also be seen in commuting methods of travel, for example car or van pooling for dropped from 9.8% (2011) to 0.7% (2021).
- As a result of these impacts change-over-time analysis of travel was not included in Census 2021 bulletins for this topic. However, there appears to have been a lasting change in the main workplace location for many people, with the prevalence of working from home appearing to remain higher than pre covid levels.
- Significant efforts were made to minimise any such impact on student populations, consequently the location and method of travel to place of study data is not significantly impacted (see Census 2021 student information paper).
Migration
- Migration-related statistics were influenced by pandemic-related travel restrictions.
- Though the exact impact of these restrictions cannot be quantified, the data remains useful for understanding migration patterns between March 2020 and March 2021.
- These changes should be considered when comparing with data from previous years.
- Additional Northern Ireland migration statistics pre and post Census 2021 are available on the Mid Year Population Estimates pages of the NISRA website.
Alternative populations release
- The pandemic led to rapid changes in employment and study locations.
Individuals on furlough may have misreported their employment status. - Due to travel restrictions, the locations where people worked or studied were affected.
- A post-collection process was used to adjust for student overcounts and duplications providing robust estimates for this group (see Census 2021 student information paper for more information).
- The information published is an accurate representation of census day, however, comparisons with Census 2011 alternative populations statistics should be made with caution.
Origin-destination (migration and travel flows)
- Census 2021 migration and travel statistics were impacted by widespread travel restrictions.
- Student migration patterns were especially affected:
- Many students may have stayed at parental homes for the entire academic year.
- Fewer international students may have resided in Northern Ireland.
- Graduates in 2020 were seeking employment under lockdown and restricted movement.
- These factors likely led to significant changes in post-education migration trends.
- As with other topics, while the impact of these restrictions cannot be precisely measured, the data remains valuable for understanding broad movement trends during this period. But comparison to other points in time should be made with caution.
Summary
Census 2021 data offer an accurate snapshot of the Northern Ireland population on census day 2021. The overwhelming majority of the information gathered was unaffected by COVID, but the pandemic did distort some data compared to pre covid society – despite the measures NISRA put in place to account for them (for example, online advice, change in enumeration strategy, moving students to term-time addresses).
The affects of COVID are most evident in the data related to work location, method of travel to work, and migration in the year before census. While Census 2021 data still offer meaningful insights of census day for these topics, analysts and users should apply caution when making comparisons with data from previous censuses or using this data for detailed trend analysis.
Each statistical bulletin for the individual topics (available at Census 2021 statistical bulletins) made reference to comparability with earlier censuses in their respective "Further information" sections.