Interviewing Black Belts – Sifting through Candidates for Gold

interviewing black


Having interviewed dozens of black belts for positions in the past, I know that finding legitimately trained and competent Lean Six Sigma black belts is a challenge in the U.S. and Canada.

“I have gone through over 30 interviews to fill one black belt position and still haven’t found one.”

When I heard this statement come from a Lean Six Sigma black belt acquaintance a few weeks ago, I was not surprised. While I admire the quest to find the right corporate fit from a personality perspective, I knew this person was not referring to that, but rather to the challenge of finding a black belt who was truly technically qualified (and therefore capable of helping his business achieve process excellence, cut costs, and bring more money in).

What does it mean to be a qualified Six Sigma black belt?

For those of you unfamiliar with the belt structure and nomenclature, the most common and consistently acknowledged belts are as follows:

  • Green belt – trained with one project completed realizing financial benefits
  • Black belt – trained with two projects completed realizing financial benefits and ability to train green belts

The elusive high caliber black belt – why are they so hard to find?

The problem of finding competent black belts boils down to two issues:

  1. Unfortunately, many programs certify individuals for just going through training or completing a group project (multiple green belts on one project)
  2. There are no internationally recognized standards for training or certification body in the Lean Six Sigma community

I was very fortunate going through my Lean Six Sigma black belt training because my trainer and certifier was extremely rigorous to ensure integrity of his program. His certification rate was just over 50%. You were not automatically certified just going through the training, you had to earn it by also completing the individually managed projects successfully.

Step 1: Ask these two interview questions to sort through the applicant pool clutter

When I interview potential candidates, I always ask two questions:

  • “Can you walk me through one of your projects?”
  • “What sort of statistical analysis methods you have used in the past?”

In order to assess their credibility through their answers, you have to know a little about the project framework for Lean Six Sigma. Most projects will follow the D-M-A-I-C framework (pronounced duh-may-ick) because this method is utilized to repair business process failures causing an undesired state.

Step 2: A real black belt will be able to walk you through their DMAIC framework and how they used it to complete their project

  • Ask them what their “Primary Y” or primary metric was. All Lean Six Sigma projects rely on moving a primary metric from a current state to a desired state
  • As they wrap up their answer, really press for what the primary metric or primary Y moved from and to during the course of their project
  • Ask them what the business benefit was

If their answers do not make sense or they dance around the questions move on to the next candidate.Your cheatsheet: DMAIC stands for Define, Measure, Analyze, Improve, and Control

From a high level, the Define stage is used to identify your project charter and scope, form your subject matter expert team and initial business case, and identify metrics that will assess success of the project.

The Measure stage forms a measurement plan to understand the business process, value stream map it, and quantify the areas that may be causing the undesired outcomes.

The Analyze stage is used to do detective work and perform statistical tests to find your root cause(s) to the undesired state.

The Improve stage is as simple as it sounds: design solutions that eliminate the root cause(s).

The final stage, Control, is forming a control plan to sustain your solutions and success as you transition away from the project.

Step 3: If your candidate does not know common statistical terms, pass on them

Next, move on to questioning them about their statistical knowledge. One of the main factors that turn people away from learning Lean Six Sigma is the application of statistics. However, if you are a black belt, you have to know a series of different statistical tests and applications in projects. Hypothesis testing is almost always used in any project – t-tests, regression (f-tests), z-tests, chi-squared tests, etc.

Ask them if they know how to do Statistical Process Control (SPC) charting, Design of Experiments (DOE’s) and Process Capability Analysis.

Using these three simple steps in interviewing, you can easily sift through candidates to find the right one for your organization. Keep sifting, like my colleague, and you’ll eventually find gold.

What questions do you have about interviewing and identifying knowledgeable black belts? We’ve helped companies like yours find and keep talent. Leave us a comment below, or contact our team of cross-functional performance improvement specialists today for personalized support.