Source of a number
The source of a number is where a recorded calorie or macro figure came from: a label, the person who ate, a reference table or an estimate. IZeat stores a source with every item it records, echoes it in every reply, and shows it on every screen, so a customer can always tell a measured figure from a reasoned one.
Four sources exist and each item carries one: label, read from packaging; user, given by the customer; reference, a plain weighed food valued from a composition table; and estimate, deduced by the assistant. A label beats a customer's figure or a reference value, which beat an estimate. The rule behind it is the first rule of the product: no invented macro. An estimate is a useful thing; a guess dressed as a measurement is not, and the community that quit other trackers says so in its own words.
A number without a source is a number the person cannot argue with, and arguing with a number is how a record gets corrected. Sources are also what lets IZeat keep its promise not to build a blended food database of its own: reference values stay attributed to the table they came from, labels to the packaging, estimates to the assistant. The customer can export all of it, sources included, in one click.
Put it into practice: Estimates and sources.
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