Hi Dirk,
I want to check the validity of the refinement of anisotropic B-factors vs. > TLS + isototropic B-factors using the Hamilton R-value ratio test as > described in Ethan Merritt's paper "To B or not to B", Acta Cryst. D, Vol > 68, pp 468. This test uses the generalised R-factors (assuming unit > weights), RG=(Sum(Fo-Fc)^2/Sum(Fo)^2)^1/2. Although Hamilton wrote that > at the end of refinement, one could also use the similar ratio of the usual > R-factors, I really would like to check the ratio of the RG-values after > refinement. As far as I can see, this value is not reported by the usual > refinement programs. R factor is a global metric that, if considered alone, is not going to answer your question. Best is to consider all three: 1) Rfree; 2) Rfree-Rwork; 3) Meaningfulness of refined TLS matrices. Note, as we discovered and documented recently, results of TLS refinements (TLS matrices) are nonsensical in 85% of PDB entries (yes, eighty-five are bad, believe it or not!): >From deep TLS validation to ensembles of atomic models built from elemental motions A. Urzhumtsev, P. V. Afonine, A. H. Van Benschoten, J. S. Fraser and P. D. Adams Acta Cryst. (2015). D71, 1668-1683. I'd say if you pass "1-3)" you are more than good. If still in doubt, you can make an extra effort and do what's described in Validation of crystallographic models containing TLS or other descriptions of anisotropy F. Zucker, P. C. Champ and E. A. Merritt Acta Cryst. (2010). D66, 889-900 which may reveal extra troubles. All the best, Pavel
