the 80/20 rule
noun[S]
MANAGEMENTukus(alsothe 80/20 principle)aprinciplestatingthat 80percentofproblemsoreffectscome from 20percentofcausesfor aparticularevent:
Use the 80/20ruletoincreaseyourwebsite’seffectivenessbyfocusingon the 20% that willbringyou 80% of theresults.