Components kept separate, in the value's unit (literature SCHEMA.md, UNCERTAINTY_CALIBRATION.md): effective = max(sqrt(max(printed, reading, method)^2 + composition^2 + conversion^2), scatter). The method floor is the robust between-study scatter of the method class in ORCHID (calibrated) or a documented prior; printed values and printed uncertainties are unchanged.
Uncertainty budget of the literature values of Al9Sr5
Value
Unit
Printed
Reading
Method (class, basis)
Composition
Scatter
Conversion
Effective
-29.4
kJ/mol-atom
0.05
8.395 (dft, calibrated)
8.395
-27.7
kJ/mol-atom
0.05
8.395 (dft, calibrated)
8.395
Sources
Yu Zhong, C. Wolverton, Y. Austin Chang, Zi-Kui Liu, A combined CALPHAD/first-principles remodeling of the thermodynamics of Al–Sr: unsuspected ground state energies by “rounding up the (un)usual suspects”, Acta Materialia 52, 2739-2754 (2004). doi:10.1016/j.actamat.2004.02.022