Mean accuracies of methods using the 'PAM Variable Rates' Model. Error Bars are Standard Errors. Percentage Accuracies are calculated for variable sites only (see text for details). The Percentage Accuracy for all sites is higher in all cases (Data not shown). The 'PAM Equal Rates' and 'Random Equal Rates' Models gave very similar results (Data Not Shown). Data shown includes only those phylogenies that did not crash CODEML (see text).