Health & Fitness

A formula with a name on it, or nothing

The rule this category is built on is that every number has an author. BMI is Quetelet’s index with the World Health Organization’s bands over it. A basal metabolic rate comes from a named equation, and different equations disagree by enough to matter. A due date is counted from a convention about cycle length rather than from an observation. Body fat from tape measurements is a regression fitted to a particular population.

Naming the source is not decoration. It is the only thing that lets you tell an answer you can act on from an answer that happens to apply to somebody else — and it is why the tools here show the band, the equation or the convention alongside the figure rather than presenting a single confident number.

It also sets the limits honestly. A screening statistic built to describe populations does not become a personal assessment because you typed your own height into it, and the pages say so.

The one tool here that talks to the internet

Every other tool on the site does its arithmetic entirely in your browser. The product ingredient checker is the single exception across all 175, and it is worth stating in the open: when you enter a barcode, that barcode is sent to Open Food Facts, a public open-data project, in order to look the product up. Nothing else about you goes with it, and the additive information the tool matches against comes from the Open Food Facts additives taxonomy, used under its open licence.

If that is not a request you want made, the rest of the category never makes one. The screener, the calculators and the converters all work with the tab offline.

The screener is quoted, not written

The ADHD self-report screener is the six-question Adult Self-Report Scale (ASRS v1.1) Screener, reproduced word for word. Its questions, its instruction line, its age statement and its scoring rubric are the instrument’s own text under the licence its rights holders publish it under, which permits an electronic version and permits no other modification.

That constraint is the point. The wording is the instrument: a reworded item is a different item with no validation behind it, and would read better while measuring nothing. What the tool adds is the arithmetic and the handover sentence — that a result consistent with adult ADHD is a reason to talk to a clinician, and never a conclusion in itself.