The IASSC Lean Six Sigma Black Belt exam is organised around the same five DMAIC phases as the Green Belt, but tested in greater depth. Rather than headline percentage weights, learn the tools by phase - and, at Black Belt level, by the data situation they fit. The advanced statistics concentrate in Analyze and Improve, which is where most candidates lose marks. Confirm the current body of knowledge on the IASSC certification page.
| Phase | What it covers |
|---|---|
| Define | Selecting and scoping larger projects, voice of the customer, CTQs, problem statement, project charter, leading and coaching the team |
| Measure | Process mapping, data types, measurement systems (MSA), descriptive statistics, process capability |
| Analyze | Inferential statistics and hypothesis testing (including non-normal data and group comparisons), correlation, regression |
| Improve | Multiple regression, design of experiments (DOE), generating, piloting and implementing improvements at scale |
| Control | Control plans, statistical process control (SPC), sustaining the gains |
Where the Black Belt goes deeper than the Green Belt
Three areas mark the step up from Green Belt, and they deserve the most study time:
- Analyze - inferential statistics. Beyond Green Belt basics, you choose and interpret the right hypothesis test for the data, including non-normal cases and comparisons across groups.
- Improve - design of experiments (DOE). Black Belts plan experiments to study several factors at once and read the results, rather than changing one thing at a time.
- Improve - multiple regression. Modelling an output from several inputs together, not just a single-variable relationship.
How to study it
Learn each tool in the context of its DMAIC phase, and at Black Belt level also tie each statistical tool to the type of data it suits. Put the most time into the Analyze and Improve statistics - hypothesis testing for different data types, multiple regression and DOE - because they are the genuinely new, heavily represented material. Remember there are several Six Sigma bodies (IASSC, ASQ and others); study the IASSC body of knowledge if you are taking this route. Confirm the current curriculum on the IASSC certification page.