Analyze: This phase is used to find the reasons for poor performance. The objective of this phase is to understand why defects are generated. Brainstorming and statistical tools are used to identify key variables that cause defects. The output of this phase is the explanation of the variables that are most likely to affect process variation. Finally the recommended solutions are implemented in the next phase - Improve.
Improve: The objective of this phase is to confirm the key variables and quantify the effect of the se variables on the CTQs. It also includes identifying the maximum acceptable ranges of the key variables, validating the measurement systems and modifying the existing process to stay within these ranges.
Control: The objective of this phase is to ensure that the modified process now enables the key variables to stay within the maximum acceptable ranges, using tools like Statistical Process Control (SPC), simple checklists or we can say this phase is used to find the deviations from the recommended method to the actual progress and reasons for deviations will be analyzed