Effective capacity refers to

the expected output that an operation can produce continuously, at the maximum rate without stopping

the output of an operation considering both planned stoppages and unplanned losses (e.g. poor work rate, absenteeism, new staff training)

the difference between design capacity and actual capacity of the organisation

the expected output of an operation considering planned stoppages (e.g. maintenance, shift changeovers, delays)

the effectiveness of an organisation in managing its production capacity