# How do you calculate the top L/5 score?

I am currently investigating how to predict protein structure and contact map predictions. There, I see things like top L/5 and top L/2 scores as a way to evaluate the contact map. What formulas do you use to evaluate these? Also, what is a meaningful evaluation method?

• L is protein length so you divide that by two or five! Sorry, I could not resist that. Anyway, there are a few metrics to rank the contact, so depends on the paper. The original EVFold paper is a good place to start journals.plos.org/plosone/article?id=10.1371/… even if you are interested in the AlphaFold stuff. Nov 18, 2020 at 12:25
• @MatteoFerla Thanks for answering my question, I understand that L/5 is the length of the protein sequence divided by 5. Does that mean that Top L/5 represents the best prediction for all patches of L/5? Nov 21, 2020 at 10:22
• @MatteoFerla Also, what does Short, Medium and Long mean in the accuracy column of the forecast? This is the paper: academic.oup.com/bioinformatics/article/35/22/4647/5487385 Nov 21, 2020 at 10:23
• That sounds like the range cutoffs —A range contact is not the distance of atoms, but the distance in residues in the linear sequence —in that paper <12 is short, >23 long. Honestly, I've not read that paper —the Zhang group have made I-Tasser so are a good group. But this is paper dependent, in the AlphaFold one they divide the range in 64 bins, but still refer to short-range/medium-range/long-range. Nov 21, 2020 at 12:10