For many employees, experienced or less experienced, the variety of problem-solving approaches is confusing. But there are not so many differences between these approaches, as one could expect. All differences are depending only on the type of problem, which has to be solved.
The various problem-solving approaches like PDCA, A3, DMAIC, 8D and so on can be sorted in the following categories:
- Is it a small, medium or large sized problem you want to solve and is the solution of the problem unknown?
- Does your problem solving strategy follow a continuous improvement process or do you want solve a single problem (e.g. a customer complaint)?
All these approaches have in common, that they follow a scientific and methodic way to solve the problem. In addition to that, the different phases in each approach can be mapped to the phases of the other ones (please see table below).
PDCA: The PDCA-Cycle, also called the Deming-Cycle or Shewhart-Cycle, is the classic problem-solving approach in a LEAN environment. PDCA is used for medium sized problems and the Act-phase implies that the PDCA-Cycle should start again in the sense of a continuous improvement process. The Plan-phase should be done very careful and therefore should consume at least 50% of the total time of the PDCA.
A3: The A3-Report, developed by Toyota, is an 8-step PDCA that should fit on an A3 sheet of paper. It is a collaborative and visual tool (graphs should be included). The A3 is also used for solving medium sized problems, which can be solved in approx. one week or less. A3-Reports are very common in the LEAN world.
DMAIC: The origin of the DMAIC problem solving approach is the Six Sigma world. Basically, it is a 5-Step PDCA used for large problems where typically a huge amount of data is available. Therefore DMAIC is often related with statistic tools, but this does not have to be. The duration of a DMAIC project may exceed more than three months, dependent on the complexity of the problem and process to be improved.
8D/PSP: The 8D problem solving process, or 8D-Report, is often used in automotive industries. It is an 8-step PDCA with focus on fast reaction to customer complaints (e.g. a delivered component or product failed at the customer or in the field). Typically the first three steps should be accomplished and reported to the customer in three days. Basically PSP is the same thing like the 8D, but used in aerospace industries.
And what’s about the small sized projects? Well, these are “just do it” projects, also known as Kaizen Blitz in the LEAN Six Sigma world.