Ancient Monuments and Woolworths Stores

Ben Goldacre at the Guardian: passes on the story of a New Age archaeologist who was tripped up because a real scientist took the trouble to analyze his work. English "researcher" Tom Brooks

analysed 1,500 prehistoric monuments, and found them all to be on a grid of isosceles triangles, each pointing to the next site, allowing our ancestors to travel between settlements with pinpoint accuracy. . . . Brooks has proved, he explains, that there were keen mathematicians here 5,000 years ago, millennia before the Greeks invented geometry: "Such is the mathematical precision, it is inconceivable that this work could have been carried out by the primitive indigenous culture we have always associated with such structures … all this suggests a culture existing in these islands in the past quite outside our expectation and experience today." He does not rule out extra­terrestrial help.

It looks impressive at first, and at least two major English papers carried the story, but you have to remember that he had 1,500 sites to work with. Mathematician Matt Parker showed the fallacy behind this sort of reasoning by doing a similar analysis of Wooldworths stores:

"We know so little about the ancient Woolworths stores," he explains, "but we do still know their locations. I thought that if we analysed the sites we could learn more about what life was like in 2008 and how these people went about buying cheap kitchen accessories and discount CDs."

The results revealed an exact and precise geometric placement of the Woolworths locations.

"Three stores around Birmingham formed an exact equilateral triangle (Wolverhampton, Lichfield and Birmingham stores) and if the base of the triangle is extended, it forms a 173.8 mile line linking the Conwy and Luton stores. Despite the 173.8 mile distance involved, the Conwy Woolworths store is only 40 feet off the exact line and the Luton site is within 30 feet. All four stores align with an accuracy of 0.05%."

Parker used an ancient technique: he found his patterns in 800 ex-Woolworths locations by "skipping over the vast majority, and only choosing the few that happen to line up".

With 1,500 locations, Brooks had almost twice as much data to work with, and on this issue Parker is clear: "It is extremely important to look at how much data people are using to support an argument."

Parker concludes that “these incredibly precise geometric patterns mean that the people who founded the Woolworths Empire must have used these store locations as a form of ‘landmark satnav’ to help hunters find their nearest source of cheap sweets that can be purchased in whatever mix they chose to pick. Well, that or the fact that in any sufficiently large set of random data it is possible to find meaningless patterns of any required accuracy.”