Abstract
The study establishes the degree to which terrorist organisations are successful in achieving their stated goals and objectives. The analysis is undertaken within the framework of the strategic actor theory, which argues that terrorist organisations are rational actors that undertake a series of calculated actions towards the achievement of predetermined goals. The Key Performance Indicator (KPI) methodology, borrowed from the discipline of Management, was used as the analytical framework to measure the performance of the Islamic State. The study notes that the Islamic State's ideology and brand continue to attract sympathisers, but the organisation has lost significant territory, financial resources, and the ability to carry out terrorist attacks that produce mass casualties. This has undermined the attainment of its key goals of spreading radical Islam worldwide and establishing a caliphate in the Levant.