Landmark Numbers

 When The Blob was very young, I wrote skeptically about a sewer-clogging fatberg being the size of a double-decker bus. My calcs suggested it was much smaller. I'd didn't object to the metaphor, however, because, for Brits and their neighbours a double-decker is a) familiar to all but the most rural folk b) bigger than a bread-box but smaller than a building and so a convenient unit of measurement. Matt Parker and Tim Harford agree:

They are discussing, physically distanced, Landmark Numbers which aspire to being the Linnaean binomers of guesstimation and journalism . . . to facilitate communication between two people with different backgrounds by appealling to the common experiences. Being international quants, they provide conversion units for foreigners [1 bus = 30 feet]. Of course in science we have the metric system, and pretty much the whole world has some idea of what a kilo[gram], a litre, a metre, and 100km/h is. Actually, probably not: the majority of my students only know their height in feet & inches. And I guess most people would have to be reminded that a standard bag-of-sugar is 1 kg & so is a litre of milk.

Matt Parker holds that human days per year is a good divisor for, say money or work: it's about 1.7billion for Ireland; about 15x more for the UK and about 70x more for the USA. But it's definitely important to know how many people live in the same country as you. If the Minister of Quangos is talking large that s/he's allocated €5 million to some project it sounds big, like a lotto win . . . but it's only €1 for each of us in Ireland. Landmark numbers help us map the real world. Islamabad and Dehli are only about an inch apart on the map but in reality it's 670km - much further than Cork to Belfast. It's also important to know how big your country is in kilometres or hours sp you can realistically plan your staycation in The West

Here's Tim Hartford having a go at Darrel Huff author or How to Lie with Statistics [and fake news]; because Huff took his glib accessible book literally and started lying for big business. And

here's an engineer's example of trying to get make Landmarks for the world's biggest dams.