Everyone knows about the importance of continuous improvement in any development project. Most people have heard about the term "Kaizen". Is means simply "improvement" but is typically applied for to measures for implementing continuous improvement. Kaizen is a daily activity, the purpose of which goes beyond simple productivity improvement. 

The cycle of well performed continuous improvement can in simple terms be defined as:

• PLAN Establish the objectives and processes necessary to deliver results in accordance with the expected output. By making the expected output the focus, it differs from other techniques in that the completeness and accuracy of the specification is also part of the improvement.
• DO Implement the new processes. Often on a small scale if possible.
• CHECK Measure the new processes and compare the results against the expected results to ascertain any differences.
• ACT Analyze the differences to determine their cause. Each will be part of either one or more of the P-D-C-A steps. Determine where to apply changes that will include improvement. When a pass through these four steps does not result in the need to improve, refine the scope to which PDCA is applied until there is a plan that involves improvement.

The concept of the continuous improvement cycle is based on the scientific method and can be written as "hypothesis" - "experiment" - "evaluation" or plan, do, and check. A fundamental principle of the scientific method is iteration - once a hypothesis is confirmed (or negated), executing the cycle again will extend the knowledge further. Repeating the cycle can bring us closer to the goal, usually a perfect operation and output. In other similar theories it can be desribed as "define, measure, analyze, improve, control".

PDSA should be repeatedly implemented in spirals of increasing knowledge of the system that converge on the ultimate goal, each cycle closer than the previous. One can envision an open coil spring, with each loop being one cycle of the Scientific Method - PDSA, and each complete cycle indicating an increase in our knowledge of the system under study. This approach is based on the belief that our knowledge and skills are limited, but improving. Especially at the start of a project, key information may not be known; the PDSA - scientific method - provides feedback to justify our guesses (hypotheses) and increase our knowledge. Rather than enter "analysis paralysis" to get it perfect the first time, it is better to be approximately right than exactly wrong. With the improved knowledge, we may choose to refine or alter the goal (ideal state). Certainly, the PDSA approach can bring us closer to whatever goal we choose.

Rate of change, that is, rate of improvement, is a key competitive factor in today's world. PDSA allows for major 'jumps' in performance ('breakthroughs' often desired in a Western approach), as well as Kaizen (frequent small improvements associated with an Eastern approach). In the United States a PDSA approach is usually associated with a sizable project involving numerous people's time, and thus managers want to see large 'breakthrough' improvements to justify the effort expended. However, the Scientific Method and PDSA apply to all sorts of projects and improvement activities.