Within each KPA, a number of more specific "Focus Areas" are identified in which there are potential intentions to establish performance management. Focus Areas are typically needed where performance issues have been identified.
Doc 9883 Manual on Global Performance of the Air Navigation System, first edition, 2009
For example, within the Capacity KPA one can identify network capacity, airport capacity and airspace capacity as Focus Areas. There may be a need to define hierarchical groupings of Focus Areas.
Lexicon Release 2016.1