This is defined as a permanent facility that possesses the technical conditions necessary to hold any type of stage production. The following criteria have been established in order to conduct the census:

• Only theatres whose scheduling mainly consists of professional productions have been considered. In theatres where an additional part of the scheduling is dedicated to amateur performances, these have been taken into consideration for accounting purposes. Theatres that only host amateur productions were left out of the statistics.
• Only theatres that have at least 3 professional performances scheduled throughout the year have been taken into consideration.
• Of the theatres' activities, only the scheduling of performing arts and music has been taken into account, excluding cinema, conferences, meetings and miscellaneous events.
• Theatres are classified according to revenue generated: large theatres have a revenue of more than 1 million euros; medium theatres take between 100,000 and 1 million euros; and small theatres take less than 100,000 euros in revenue.