Process Sigma calculation
During the Measure phase of a DMAIC project, the team uses information about customer requirements and process defects to calculate process sigma. This is a measure of the extent to which process performance meets customer requirements, and is related to the amount of process variation and to the specification limits established by gathering customer feedback. In some cases a preliminary measure is available during the Define phase, but it is refined during Measure once more detailed feedback from customers is obtained and the problem statement is clarified.
Brainstorming is a technique often used in Six Sigma projects. In the Analyze phase of DMAIC it is used to come up with a comprehensive list of potential root causes for the problem that project team aims to solve. In the Improve phase or in a Design For Six Sigma (DFSS or DMADV) project, it is used to come up with a creative and thorough list of possible ways of making an improvement or creating a product or service. The keys to brainstorming is to withhold judgment during the idea generating portion and to ensure that everyone involved gets a chance to contribute ideas. It may be necessary to use a variety of brainstorming techniques to get different types of participants contributing and to bring out innovative ideas.
The Kano model is used as part of establishing customer requirements in DMAIC and DMADV projects. It involves gathering data from customers about a product or service to determine which features must be included for them to be satisfied, which features are not expected but would delight them, and which features will lead to greater satisfaction the more they are fulfilled. For example, anyone buying a television now would likely insist that it have remote control and a clear picture and be cable ready, but would not expect it to have a built-in stereo, built-in picture frames, or a self-cleaning screen. And typically, the larger the screen for the price, the better. Business leaders need to be sure that they meet the "must be" requirements or it doesn't matter what other features and options are provided.
Statistical data analysis
Often DMAIC projects require the use of advanced statistical techniques such as Analysis of Variance (ANOVA), Chi-square analysis, regression analysis, or other tests. In most cases at least a simple t-test or correlation analysis is necessary. Data analysis typically happens during the Measure phase while analyzing detailed data about the process and problem, occasionally in the Analyze phase while confirming root causes, and again in the Improve phase when making the before-and-after comparison.
Design of Experiments
Design of Experiments (DOE) is a technique used in the Improve phase of DMAIC projects to test different variations of a solution to determine which produces the best or desired result. It requires an understanding of how to properly establish sample sizes and conditions for the trials, and is essentially applying the scientific method to a business process. Software such as Minitab can assist with creating a proper DOE for a Six Sigma project.
House of Quality (Quality Function Deployment)
The House of Quality (HOQ) or Quality Function Deployment (QFD) is a core tool used for a Design For Six Sigma project. Using this method, the project team establishes customer requirements, explores metrics for tracking performance relative to those requirements, and evaluates potential means of implementing the final product or service.
Some Six Sigma initiatives also incorporate Lean principles and tools into their programs. Thus Lean tools such as Value Stream Mapping (VSM) and Kaizen may also be used for Six Sigma projects.