Currently, most protein structure prediction methods use one or at most a few QA methods to rank and select models, generally leading to the poor performance in selecting models of good quality due to the extreme difficulty of ranking models and intrinsic limitations of individual QA methods.
The MFRM analysis showed that while the descriptors at C1 level were generally ranked as expected, teachers had difficulties in ranking descriptors at the CEFR B1, B1+ and B2 levels.
The first difficulty with rankings is that it can be surprisingly hard to measure the variable you want to rank — even in cases where that variable seems perfectly objective.
How on earth does anyone propose to assign a number to something like that?The first difficulty with rankings is that it can be surprisingly hard to measure the variable you want to rank even in cases where that variable seems perfectly objective.
There are difficulties in ranking schools according to the town or city they are in.
Difficulties in ranking coordinations were the cause of 6.8% of the total errors.
However, there are difficulties in ranking tennis players: the tournaments are played on different surfaces (grass, clay, synthetic, etc).. Most players have a favorite surface, and their performance level changes with different surfaces.
In this week's episode, "Soloists," dancers discuss the difficulty of soloist ranking -- a seniority based ranking system that can chip away at a dancer's confidence.
If an informant had difficulty in providing options for ranking during the ranking exercise, typical challenges as described in the literature were written on pre-manufactured cards and proposed for the participant to consider.
The bigger difficulty with the rankings is that of the "halo" effect where, in the words of Simon Marginson, professor of international higher education at the Institute of Education, "existing reputation drives judgement".
We interpret this to mean that when differences between included and excluded studies are slight, (i.e., presentation in the Cochrane excluded study list is warranted) a relevance-ranking search engine will have difficulty distinguishing relevant from irrelevant items on the basis of the information contained in the bibliographic record.
