Competitive Ranking
All Ranking done by IPRO on its measures is done using the Competitive Ranking Method. In Competitive Ranking, all eligible values are arranged from high to low (or low to high in the case of less_is_more measures) and assigned ranks ascending from 1. In the event of a tie, all tied values are assigned the lowest available rank, and ranking is resumed regularly for the next value after the tie. For example, if values v2 and v3 are tied, ranking with v1 being best and v4 being worst, competitive ranking would be:
- v1: rank 1, example value = 100
- v2: rank 2, example value = 90
- v3: rank 2, example value = 90
- v4: rank 4, example value = 80
In Pellucid, items that compare equal receive the same ranking number, and then a gap is left in the ranking numbers. The number of ranking numbers that are left out in this gap is one less than the number of items that compared equal. Equivalently, each item's ranking number is 1 plus the number of items ranked above it.
This ranking strategy is frequently adopted for competitions, as it means that if two (or more) competitors tie for a position in the ranking, the position of all those ranked below them is unaffected (ie, a competitor only comes second if exactly one person scores better than them, third if exactly two people score better than them, fourth if exactly three people score better than them, etc).
Thus if A ranks ahead of B and C (which compare equal) which are both ranked ahead of D, then A gets ranking number 1 ("first"), B gets ranking number 2 ("joint second"), C also gets ranking number 2 ("joint second") and D gets ranking number 4 ("fourth"). In this case, nobody would get ranking number 3 ("third") and that would be left as a gap.
Competitive ranking occurs independently of percentile ranking.