Methodology

Each CostMage page is a typed cost record. The record states its evidence class, source family, data period, limitations, and whether an estimator formula is allowed.

What we publish

• Official unit prices and fee schedules when a primary source states them.
• Cited ranges when that is all the source supports.
• Labeled derived figures only when the arithmetic is locked to a sourced configuration.

What we do not do

• Invent ZIP-code or state multipliers.
• Blend two different series into a fake typical.
• Render calculator controls without a validated formula ID, inputs, units, and source basis.
• Present an internal evidence-quality score as the probability that your bill matches the figure.

How to read a result

• A quantity total is sourced rate times your quantity. The publisher did not print that total as your bill.
• A unit-price gap is your typed price minus the locked rate. It is not a finding that someone overcharged you.
• A band check says below, inside, or above a published range. It does not invent a midpoint and call it typical.

Evidence confidence

Public labels such as “High evidence confidence” describe source strength. They are not a statistical confidence interval around the cost itself.