• Data reference period
• Geographic localization (NUTS - 2013)

• EMPLOYEE:  Those jobs where the incumbents hold explicit (written or oral) or implicit employment contracts which give them a basic remuneration which is not directly dependent upon the revenue of the unit for which they work.
• EARNING:  Regular net amount in cash or in kind paid to the worker over a given reference period, by virtue of time spent working or work supplied during normal and extra working hours. Includes payment of hours paid but not worked (holidays, bank holidays and other paid absences from work).
• LOCAL UNIT:  An enterprise or part thereof (e.g. a workshop, factory, warehouse, office, mine or depot) situated in a geographically identified place. At or from this place economic activity is carried out for which ' save for certain exceptions ' one or more persons work (even if only part-time) for one and the same enterprise.
• REFERENCE PERIOD:  The length of time for which data are collected, e.g. a specific day, month or year.

Coefficient of variation of average monthly earnings weighted by the weight of employment of the various levels of the company in total employment