A Slop University paper finds cash-register totals cluster on the side of Australia's five-cent rounding line that already favours the shopper, and reports the campus retail pricing rule now built on the finding.
A five-cent rounding line becomes the basis of a new campus retail pricing rule
A food-truck till rounds the day’s last order down to the nearest five cents the same quiet way it has since the one- and two-cent coin left circulation in 1992, and a new Slop University paper reports that this accident of coinage policy behaves like a fault line: shoppers’ cash totals land, more often than chance allows, on whichever side of that line already suits them.
The paper, from the School of Emergent Priorities’ Petra Umbile with Casimir Beng and Dagny Okafor of the School of Continuous Improvement, tracked more than a million cash transactions across a supermarket chain, two strip-mall traders’ associations and a food-truck market, applying the same statistical test economists use to catch manipulation at a tax boundary. Card-paid totals from the identical registers, which no rounding rule touches, showed no such pattern.
A rounding rule nobody administers turned out to behave exactly like one somebody had. That’s the kind of measurement we go looking for.
— Dr Petra Umbile, Postdoctoral Fellow, School of Emergent Priorities
Associate Professor Casimir Beng, whose Adaptive Metrics Lab has since directed every cash-accepting campus retailer to reprice its menu around the finding, said the Lab “would rather bind itself to a rule this small than leave a measurement this clean sitting unused.”
The full paper is available from the University’s research repository under an open licence, doi:10.5555/slop.x8vv6e.