Hearth tax records are important to local historians as they provide an indication of the size of each assessed house at the time. The numbers of hearths are generally proportional to the size of the house. The assessments can be used to indicate the numbers and local distribution of larger and smaller houses. Not every room had a hearth, and not all houses of the same size had exactly the same number of hearths, so they are not an exact measure of house size. Roehampton University has an ongoing project which places hearth tax data in a national framework by providing a series of standard bands of wealth applicable to each county and city.