Their purpose is different to that of indicators underlying an index of deprivation, and many are survey-based or otherwise do not lend themselves to measurement at a small area level.
Mae eu diben yn wahanol i ddiben dangosyddion sy'n sail i fynegai amddifadedd, ac mae llawer ohonynt yn seiliedig ar arolygon neu'n anaddas fel arall ar gyfer mesur ar lefel ardaloedd bach.