Hi Maher, (...) how to calculate the map correlation coefficient using Overlapamp *or > any other program*? > in addition to suggested options: - This will give you map CC calculated per residue or per atom (depending on resolution of the data): phenix.model_vs_data model.pdb data.hkl --comprehensive=true - phenix.real_space_correlation does the same plus gives you more options and controls; - PHENIX GUI -> "Comprehensive validation" will compute map CC as part of its default run, show it in various graphics, etc. Pavel.