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 BaGa2
Value
Unit
Printed
Reading
Method (class, basis)
Composition
Scatter
Conversion
Effective
-44.588
kJ/mol-atom
5.000e-4
8.395 (dft, calibrated)
8.395
Sources
Xi Li, Kaiming Cheng, Xiaoming Yuan, Dongdong Zhao, Jinghua Xin, Weiwei Wang et al., Thermodynamic assessment of the Ga–X (X=B, Ca, Sr, Ba) systems supported by first-principles calculations, Calphad 43, 52-60 (2013). doi:10.1016/j.calphad.2013.09.002