First there was the “impact factor.” Then came the “h-index.” Now, for those who believe that scientific prowess can be measured by statistical metrics, comes the Acuna-Allesina-Kording formula.
TrueSkill™ Ranking System
TrueSkill™ Ranking System
The TrueSkill™ ranking system is a skill based ranking system for Xbox Live developed at Microsoft Research.
This explains several ways to use consistent colors across plots (same way works with scales). However, the easy way explained in one of the alternative answers does not seem to work for some versions of R/ggplot2. Opting for the accepted answer always works though.
A new metrics in the works...instead of "impact factor", try "usage factor?" A majority of publishers in the Directory of Open Access Journals (DOAJ) appear to support "UF."