The code has evolved over decades to align with international metrics, shifting away from ambiguous terminology (like bias and precision) toward universal statistical concepts: PTC 19.1 - Test Uncertainty - ASME
Uncertainties evaluated by statistical methods (e.g., standard deviation of repeated measurements). asme ptc 191 pdf
Recent updates to the standard align it with international norms, classifying uncertainty by how it is calculated: The code has evolved over decades to align