Percent error vs percent difference
Percent error uses a reference denominator; percent difference symmetrically compares two peer values, so they answer different questions.
Percent error needs a reference
Use absolute observed minus reference divided by the absolute reference. A zero reference makes the percentage undefined.
Percent difference treats values as peers
A common form divides the absolute difference by the mean magnitude of the two measurements. No value is declared authoritative.
State the denominator
Do not write only “10% difference.” Name the formula and reference so a reader can reproduce the comparison.
Do not use either as proof
A small percentage does not prove accuracy or validity; the quality and uncertainty of the reference still matter.
Sources and boundaries
Solice develops LabCrux. The independent sources above do not sponsor or endorse the product. This page explains a review method; your experimental evidence, course instructions, and instructor remain authoritative.