Source hierarchy
Where a claim depends on a standard, law, government program or regulated practice, the preferred source is the responsible government, regulator or standards body. General decision methods use established definitions and visible derivations.
Illustrative examples
Worked examples use invented, rounded assumptions to demonstrate a method. They are not vendor quotations, market benchmarks or predictions. Currency symbols are illustrative unless a jurisdiction is identified.
Recommended evidence for your own model
- Contracts, quotations and validated operational records
- Direct measurements and consistent historical data
- Official government or regulator publications
- Recognized standards and institutional research
- Documented expert estimates with uncertainty ranges
Evaluate applicability
Check date, geography, industry, definitions, measurement method and incentives. An accurate statistic can still be unsuitable for another location or operating context.
Transparent formulas
The calculators use conventional arithmetic shown on their pages. They are not black-box forecasts and do not retrieve external data.