Charles Handy's four culture types, describing where authority really sits and how work actually gets done — which is often not what the org chart says.
Power culture — a central figure or small group holds control; decisions are fast, informal and personal. Common in owner-managed businesses. Fast and flexible; entirely dependent on the judgement of one person, and it stops scaling somewhere around the point they cannot know everyone.
Role culture — authority comes from position and procedure. Predictable, fair, efficient at routine work, and slow to respond to anything the procedure did not anticipate. Typical of large bureaucracies.
Task culture — power sits with expertise, organised around projects and teams. Adaptable and good at complex work; harder to control and resource-hungry.
Person culture — the organisation exists to serve the individuals in it, who are the point. Partnerships of professionals: barristers, some consultancies, GP practices.
Culture eats structure. A business that reorganises into project teams while the founder still signs off every decision has drawn a task culture over a power culture, and the drawing loses.
Diagnose from evidence in the case, then link the culture to the specific problem the business is having.