Assay: Honest Calorie Range

Every other calorie app shows one number. That number is a guess dressed as a fact — and when it is wrong, you stop trusting the app. Assay shows the range. Then it plans against the cautious end, so you are never under-planned. HOW IT IS DIFFERENT • A range, not a number. Every estimate carries a band, and the band is on screen. The oil under the plate is invisible; so is the portion under the rice. That uncertainty cannot be removed, so it is shown instead of hidden. • Two kinds of uncertainty, kept apart. Error that repeats in the same direction at every meal is systematic, and it accumulates across a day. Portion noise is random, and it partly cancels out. Adding them the same way gets one of the two wrong. Assay adds systematic error linearly and random error in quadrature — and tells you which one dominates your day. • It says when it cannot tell. A classifier that reports its…