The Census Transformation Programme will deliver the 2021 Census through three iterations.

First iteration (April 2015 to 2017 Test) – covered research and testing to develop the statistical and operational design for all three strands, including development of prototypes. This work focused on developing evidence to underpin the planning and cost assumptions resulting in revised costs for the programme and an initial design for the 2021 Census. During this phase, we carried out tests (including a large-scale field test during 2017) to validate some of the design assumptions to enable us to firm up on the design.

Second iteration (post-2017 Test leading to 2019 Rehearsal) – development and system and customer testing of the systems and services needed to support the Rehearsal. During this phase we will carry out a large-scale rehearsal of the systems and services needed to deliver the census collection, processing, analysis and dissemination operations, including any considerations required to assist with the evaluation of the Beyond 2021 design. Information and feedback from this phase will enable us to finalise the design for all three strands.

Third iteration (post-2019 Rehearsal to 2021 Census outputs) – this phase relates to the census field and processing operations, that is, the collection and processing of census information for every household, communal establishment and person in England and Wales. We’ll also collect and process administrative data to produce population statistics in parallel with the census operation. Having collected the information, this phase will analyse the data, produce and disseminate the census results, enhanced by administrative data. We’ll also analyse the results from the alternative approach using administrative data, and evaluate them against census results to provide evidence to underpin a recommendation on the future production of population statistics in 2023.

Evaluation and future planning will follow the operational phases. We’ll also make a recommendation to government on the future of population statistics in England and Wales.