PDCA

PDCA (aka the Shewhart Cycle) is an iterative four-step quality control strategy.

PLAN 
establish the objectives and processes necessary to deliver results in accordance with the specifications.
DO 
implement the processes.
CHECK 
monitor and evaluate the processes and results against objectives and Specifications and report the outcome.
ACT 
apply actions to the outcome for necessary improvement.

See also: PDCA, Quality control, Specification