The case in three lines. The Green Gazette prints THEY DON'T MAKE THEM LIKE THEY USED TO, because every 1970s bike at the repair café could be mended while a quarter of the new ones could not. A bike shop's 1978 ledger shows nine hundred bikes sold in that one year, so the thirty-six still riding are four in a hundred, the tough ones that lasted. The bike-shop owner says the story sent a mother to buy a forty-year-old bike, and Tara has to write the corrections box.

One question to ask. "What should the box say?" Then: "Was Mrs Kaur wrong that old bikes are easier to mend?" Let them argue both sides.

One thing to do at the table. Think of something people say was better in the old days, like songs, toys or films. Ask: are we remembering all of them, or only the ones good enough to still be around?

The grown-up layer. The case is about survivorship bias: judging a group by the members that made it through a long filter, while the ones that did not are missing from the count. It gives the young reporter his strongest point, that every number he printed was true. It gives the repair volunteer hers: old parts really are simpler to mend. The habits it models are going to the original log, asking where the missing ones are, and comparing like with like.

The case leaves the line blank on purpose. Ask for it before you offer yours.