The Measure phase has identified the baseline performance of the process. By stratifying (sequenced in order of ranks or order) the data in the baseline performance, it becomes possible to pinpoint the location or source of problems by building a factual understanding of existing process conditions and problems. That helps to focus the problem statement.

In the Analyze phase you will develop theories of root causes, confirm the theories with data, and finally identify the root cause(s) of the problem. The verified cause(s) will then form the basis for solutions in the Improve phase.

The tools most commonly used in the Analyze phase are:

- 5 Whys Analysis

- Brainstorming

- Cause and Effect Diagram

- Affinity Diagrams (covered in the Define phase)

- Control Charts (covered in the Measure phase)

- Flow Diagram

- Pareto Charts (covered in the Measure phase)

- Regression Analysis

- Scatter Plots

Failure Modes and Effect Analysis (FMEA)

Procedures and tools that help to identify every possible failure mode of a process or product, determine its effect on other sub-items and on the required function of the product or process. The FMEA is also used to rank & prioritize the possible causes of failure as well as develop and implement preventive actions, with responsible persons assigned to carry out these actions.

Regression Analysis

Regression analysis is a statistical forecasting model that describes and evaluates the relationship between a given variable, usually called the dependent variable, and one or more other variables, usually known as the independent variables.

Regression analysis models are used to help us predict the value of one variable compared to one or more other variables whose values can be predetermined.