Full Fact published a check on 11 July 2023 concerning a parliamentary claim that most renters lived in homes bought with a buy-to-let mortgage. Its finding turned on the difference between private renting and renting as a whole, including social housing.
Drawing on the English Private Landlord Survey, Full Fact said landlords with buy-to-let mortgages represented 61% of privately rented tenancies in the relevant historical data. But including social renters changed the denominator. Its calculation put homes financed through buy-to-let mortgages at around a third of all rented households, rather than a majority.
The check addressed a statement made on 5 July 2023. Its figures came from the available housing datasets at that time and should not be presented as a current estimate. Full Fact also distinguished private-landlord transactions from institutional build-to-rent activity when discussing changes in supply.
Why the denominator matters
Our reading is that a housing statistic needs two labels: what is being counted and the group against which it is compared. A share of landlords is not automatically the same as a share of tenancies, because owners can have different numbers of properties. A share of privately rented homes is likewise not a share of every rented home.
Before using a figure in a property discussion, write its denominator in a full sentence. For example, does it concern survey respondents, landlords, properties, occupied households or tenancies? Then record the geography and date. England-only evidence should not quietly become a UK-wide statement, and data gathered in different periods should not be combined without explanation.
This is especially useful when considering the exposure of renters to mortgage costs. The existence of borrowing, the terms of that borrowing and a household’s rent are separate pieces of information. A broad sector percentage cannot tell a tenant the financial position of their own landlord or predict their next rent review.
The archive’s value is a lesson in reading evidence carefully. It preserves the July 2023 distinction without turning it into a present-day accusation or an undated claim about the whole housing market.