Health is where social justice becomes arithmetic, because the outcome variable is death and the records are good. In Gradient mode, slide up and down a hierarchy of people who all have a job, a salary and free health care, and watch mortality change anyway. In Instrument mode, run five real clinical tools side by side — legacy version against corrected version — and hunt for the input values where the two versions disagree about the patient in front of you.
Where you stand in the hierarchy
20percentile
Adjustments
If you are in the bottom quartile, where do you live?
The surprise in 1967
Donald Reid and Geoffrey Rose enrolled 17,530 male British civil servants, expecting the executives to have the heart attacks. The opposite appeared, and it appeared as a smooth gradient rather than a cliff: each grade fared worse than the one above it, all the way to the top. Nobody in the study was poor.