Fix for NDCG Limitation
the idea is that when reporting nDCG@5 for the two results (associated to the same query) you have to use the same ideal discounted cumulative gain (in your example it would be the one from 1,1,1,1,1 which is the highest). Then the result 1,1,1,0,0
ends up penalized (nDCG@5 &lt; 1) for the missing documents.