Recently ONS published two articles showing research into the use of Valuation Office Agency (VOA) data to produce overcrowding statistics:

Estimating the number of rooms in Census 2021: an update on deriving an occupancy rating from Valuation Office Agency number of rooms The Office for National Statistics (ONS) plans to use administrative data from the Valuation Office Agency (VOA) to replace the number of rooms question on Census 2021. This article looks at the impact the use of VOA number of rooms in the 2021 Census has on room occupancy ratings, outlining the method we plan to use to account for definitional differences and asking users for feedback on the method.

Admin-based levels of overcrowding (using the bedroom standard and Valuation Office Agency number of bedrooms), feasibility research: England and Wales This article, considers the potential for using VOA number of bedrooms to support the production of sub-regional estimates of overcrowding in intercensal years (which the current surveys are unable to do due to sample size). Again, it asks users for feedback on the methods we’re proposing here.

What it shows

Due to definitional differences between the census and VOA number of rooms measures, the VOA occupancy rating is typically 1 less than the census occupancy rating at household level. To adjust for this definitional difference for the Census 2021, we recommend that the VOA room occupancy rating calculation is adjusted by adding one room. This new variable should be referred to “occupancy rating (VOA number of rooms)”.

If we adjust for this difference, the proportion of overcrowded households is likely to be smaller when using the VOA room occupancy rating compared with the 2011 Census room occupancy rating. The article explores why these differences are not consistent across the whole of England and Wales, and how they vary by tenure and accommodation type.

Currently, the English Housing Survey (EHS) publishes the most accurate national estimates of levels of overcrowding in England (using the bedroom standard). Our analyses show that VOA bedroom standard is typically the same as the census bedroom standard at household level.

The proportion of overcrowded households is likely to be larger when using the VOA bedroom standard compared with the 2011 Census bedroom standard. Most local authorities (4 out of 5) would be ranked in the same order independent of which of the two measures is used. This demonstrates the potential for supplementing household surveys with VOA number of bedrooms to produce sub-regional overcrowding statistics in intercensal years.