The megalithic yard is a hypothetical ancient unit of length equal to about 2.72 feet (0.83 m).[1][2][3] Some researchers believe it was used in the construction of megalithic structures. The proposal was made by Alexander Thom as a result of his surveys of 600 megalithic sites in England, Scotland, Wales and Brittany.[4] Thom also proposed the megalithic rod of 2.5 megalithic yards, or on average across sites 6.77625 feet.[5] As subunits of these, he further proposed the megalithic inch of 2.073 centimetres (0.816 in), one hundred of which are included in a megalithic rod, and forty of which composed a megalithic yard. Thom applied the statistical lumped variance test of J.R. Broadbent[6] on this quantum and found the results significant,[7] while others have challenged his statistical analysis and suggested that Thom's evidence can be explained in other ways, for instance that the supposed megalithic yard is in fact the average length of a pace.