Fair enough, however, when I reread the post it says: "They use a trove of data generated by Gallup, a polling firm, from its World Poll. Gallup asked responde

Fair enough, however, when I reread the post it says: "They use a trove of data generated by Gallup, a polling firm, from its World Poll. Gallup asked respondents around the world to imagine a "satisfaction ladder" in which the top step represents a respondent's best possible life. Those being polled are then asked where on the ladder they stand (from zero to a maximum of 10), and how much they earn." Not quite the same thing I said, but it still introduces a bias. The people are asked to first imagine what a "10" -- that is, their ideal, imagined happiness -- before rating their happiness. It is essentially still the same mechanic, imagining a happiness before putting your "actual" happiness against that scale.