In general I don’t put much value in certifications for process improvement methodologies. Anytime a methodology is codified, turned into a bunch of rules, the meaning is lost. What is missing is the context of the situation, and the thinking that goes into the selection of that specific tool. What are the limitations, the potential inappropriate/unexpected outcomes?
A classic example is the Six Sigma 'Black Belt.' Today many people and companies focus on obtaining or hiring people with this designation. Unfortunately, most experts teaching Six Sigma teach statistical techniques for comparison (enumerative) studies. This is the type of statistics taught in most colleges, and the course most people do not remember fondly. What is seldom taught is statistical techniques for predictive (analytical) studies.
As Dr. Deming said 'Management is Prediction.' Most business and manufacturing analysis is prediction based. Used to manage processes. Unfortunately, most Six Sigma training programs are teaching statistical tools that are completely inappropriate for predicting.
As a side note, using statistical techniques for Quality was founded by Dr. Walter A. Shewhart. In his 1931 book Economic Control of Quality of Manufactured Product he explored the tools of comparative studies for application in predictive environments. He found only a couple of techniques were useful. When data are collected and subgrouped in time sequence, only then will the calculations of 'mean' and 'standard deviation' have some usefulness for prediction. Other statistical tools he explored were less helpful.
As far as a certificate is concerned, a person can always learn enough of the wrong stuff to obtain the certification. Then forget about half of what was learned. The difficulty is to know which half to discard.
Certifications are promoted as demonstrating a certain level skill when applying tools. However, if the recipient does not know the limitations of those tools, or if a company hires someone without having intimate knowledge of the certification content, what value does certification carry?
Any one who has not heard of the certification body can easily dismiss the certification. Myself, I am certified as an 'American Samurai Warrior - First Degree' by the America Samurai Institute. A Six Sigma type certification program that is now defunct. And nobody has ever heard of it.
Given my understanding and experience with certifications, I am at a loss to guide people when they ask about certifications.