Known limitations

There are some agreed and known challenges with capturing and publishing data for Building Age, Construction Material, Basement Presence, and Number of Floors:

• There is no single, definitive measurement or information available for any of these attributes at a national scale.

• There are limited and sometimes conflicting sources of information from which to derive values.

• The real world can be very difficult to represent in data. For example, new builds can be made to look like older buildings.

• The level of estimated conformance is perfect for 1 to 2 floors 95% of the time, but it reduces with the increasing number of stories. 95% of all buildings that have 5 or more floors will have the correct number of floors value (within 1 floor) recorded when compared with the real world.

• It is difficult to accurately predict floor numbers for complex buildings with towers, spires, roof furniture, overhanging vegetation, etc.