Data Item _refine.overall_FOM_free_R_set


Item name
Category name
Attribute name
Required in PDB entries
Used in current PDB entries
Yes, in about 0.001 % of entries

Item Description

Average figure of merit of phases of reflections not included in the refinement. This value is derived from the likelihood function. FOM = I1(X)/I0(X) I0, I1 = zero- and first-order modified Bessel functions of the first kind X = sigmaA |Eo| |Ec|/SIGMA Eo, Ec = normalized observed and calculated structure factors sigmaA = <cos 2 pi s deltax> SQRT(SigmaP/SigmaN) estimated using maximum likelihood SigmaP = sum{atoms in model} f2 SigmaN = sum{atoms in crystal} f2 f = form factor of atoms deltax = expected error SIGMA = (sigma{E;exp})2 + epsilon [1-(sigmaA)2] sigma{E;exp} = uncertainties of normalized observed structure factors epsilon = multiplicity of the diffracting plane Ref: Murshudov, G. N., Vagin, A. A. & Dodson, E. J. (1997). Acta Cryst. D53, 240-255.

Data Type

Data type code
Data type detail
float item types are the subset of numbers that are the floating numbers.
Primitive data type code
Regular expression