Once the process is measured and baselines developed, the Analyze phase begins. It is during the Analyze phase where the real problems and opportunities are identified. The previously believed theories and ideas are either confirmed or disproved.

During the measure phase, the conditions and circumstances surrounding problems are determined. The Analyze phase attempts to determine why they are occurring and what can be done to improve it.

The Analyze phase uses more detailed tools for process analysis, such as “root cause problem solving” (RCPS) tools. One example is the cause and effect diagram, often called the Ishikawa diagram.

Once the root causes to problems and opportunities are identified, new solution ideas are developed that will be utilized in the Improve phase.

Six sigma has many tools for fully analyze the process to know what is happening, how and why it happens, and what might be done to improve the process.

Some of the most commonly used six sigma tools in the Analyze phase are:

> Brainstorming
> 5 Why’s
> Value Stream Mapping
> Control Charts (XBar & R, np, C, U, p)
> Scatter Plots
> Regression Analysis
> Design of Experiments (DOE)
> Hypothesis Testing