Any business entity is like an army ship that contains tanks, aircrafts, weapons and soldiers.
A torpedo can put it easily sunk into the bottom of the ocean, so there must be a pilot run to smooth the way out to the ship.
We could assume the army ship as our business entity and the pilot run is the check before moving forward to the improve action.
But as a concept, PDCA (Plan-Do-Check-Act) is the main concept of continual improvement.
So if any business entity needs improvements,
A: first it must plan for it.
B: then do on small scale.
C: check the success of this doing before,…
D: acting on the big scale – and therefore moving the ship.