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Evidence · 27 October 2026 · 8-minute read

Why Belt projects stall, and what the evidence says about coaching

Training teaches the method. The project is where it gets applied, and where many Belts get stuck. We collected every published number we could check on how many Belts finish, where projects stop and what helps. Here it is, with each source and how strong it is.

Key points

  1. Completion varies widely between programmes, from 17% to over 80% in the organisations that published a count. There is no multi-company study.
  2. Projects stop most often in Measure and Analyze, according to 201 Lean Six Sigma experts.
  3. Mentoring by a Master Black Belt ranks among the top success factors, and Black Belt competency and management support are linked to on-time completion.
  4. No study shows that software raises completion, and Taktstone has no customer results yet. Below is what we will measure in pilots.

1. How many trained Belts finish?

Five organisations published a count. They use different definitions (people certified, or projects closed), different years and different sectors, so read them as a range, not a league table.

Staples (US retail, 2011): 21 of 127 trained Green Belts certified (17%). Red Cross Hospital Beverwijk: 21 of 44 projects closed (48%). An Australian public health organisation: 62 of about 116 projects completed (≈ 53%). A research-operations programme: 14 of 20 certified (70%). Texas Children's Hospital: over 80% certified.

people certified   projects closed · hover or tap a row for the source. Single-organisation figures; not a controlled comparison, and none involves Taktstone.

What a finished project is worth, for context: published medians are about $49k for a Green Belt project and about $200k for a Black Belt project (200 Green Belt projects, iSixSigma Black Belt benchmark). Results vary by company.

2. Where projects stop

In a global survey of 201 experts, projects were most often terminated in Measure and Analyze, the phases where data, measurement and root-cause work pile up. "Inconsistent monitoring and control of the projects" was among the five main causes. A separate Minitab customer survey found that the top 8 of 42 failure reasons account for 62% of responses; by our reading, four of the eight are about choosing the project or its scope.

Most stopped projects stop in Measure and Analyze (201 experts, Antony et al., IEEE 2022). Top 8 of 42 failure reasons = 62% of responses (Minitab survey): no management support, not linked to finance, no or bad data, forced into DMAIC, too small, not enough training, scope too big, not implemented.

Hover the highlighted phases or the donut for the source. The highlighted causes are our grouping, not the survey's.

3. What helps

Two studies and the failure survey point the same way: the people around the Belt matter. Mentoring by a Master Black Belt ranked among the top four success factors in 186 responses from Indian firms. Across 256 projects in one automotive company, Black Belt competency and management support were the factors linked to on-time completion and financial results. And the absence of monitoring between reviews is a top-five cause of failure.

Mentoring by a Master Black Belt → project success (top-4 factor, 186 firms). Black Belt competency and management support → on-time completion and financial results (256 projects). Lack of monitoring and control between reviews → a top-5 cause of failure (201 experts).

Each line is one published finding; hover it for the study. These are associations reported by the studies, not proof of cause.

That is the gap Taktstone is built for: support between reviews, with the coach still deciding. Belts prepare with next steps, statistics checks and a tollgate pre-audit; the BB or MBB reviews and decides; owners sign.

  1. The Green Belt works the project.
  2. Taktstone checks it before review: next steps, statistics, tollgate pre-audit.
  3. The Belt fixes the gaps and requests a review.
  4. The BB/MBB coach approves, or returns it with comments.
  5. Sponsor and finance sign the result (server-stamped).
Every step is a feature in the product today. Click a step to open it in the live demo (fictional data).

4. Coaching hours: the arithmetic

Providers sell 6–20 hours of 1-on-1 coaching per project: 6 hours for $1,499 at GoLeanSixSigma (one for project selection and one per DMAIC tollgate), 12 hours for €3,790 at sixsigma.nl, and 20 hours of mentoring inside a $6,295 Black Belt course at the University at Buffalo. Multiply by a cohort and the coach's calendar fills quickly. Try it:

Example: 20 Belts × 6 hours = 120 coaching hours per cohort, plus 100 tollgate reviews.

Arithmetic from public price lists (checked 22 October 2026), not a measurement. Taktstone does not claim to save a number of hours; we will measure it in pilots.

5. How strong is each piece of evidence?

Most of what is published about Belt completion comes from single organisations, small samples, press releases or practitioner surveys. We grade each source: H primary source read, M abstract or secondary source, L press release or self-reported.

Peer-reviewed: Antony et al. (201 experts), Narottam et al. (186 responses), automotive study (256 projects), Monash (≈ 116 projects), Red Cross Beverwijk (44 projects). Student report: Staples (127 Belts). Practitioner survey: Minitab (≈ 150 customers). Press or vendor summary: Texas Children's (150+ staff), Nurses' Health Studies (20 staff).

Each dot is one study, placed by sample size and type of source; smaller dots are grade L. Hover or tap for details.

6. What this evidence does not show

  • It does not show that coaching causes completion: the programmes differ in sector, year, selection and definitions.
  • It does not show that any software, Taktstone included, raises completion or saves coaching time.
  • Taktstone has no customer outcome data yet. The demo projects use fictional companies and data.

What we will measure with pilot partners

  • Coach preparation time per review
  • Number of repeated review cycles per tollgate
  • Days a Belt stays blocked
  • Progress through the agreed project milestones
  • The coach's own rating of review readiness

These are measurement proposals, not established benefits. We will publish results only with the partner's permission and with the method.

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Sources

  1. Pitts & Nadeau, Improving Green Belt Project Performance for Staples, Inc., WPI Major Qualifying Project (2011). Student report, not peer-reviewed. M
  2. Six Sigma at Red Cross Hospital Beverwijk, Inderscience journal article (abstract). M
  3. Success factors for Lean Six Sigma projects in healthcare, Journal of Management Control 33 (2022). The 116 started projects is from the abstract snippet. M
  4. Nurses' Health Studies Lean Six Sigma programme, vendor summary of Am J Epidemiol (2026), doi 10.1093/aje/kwag074; the paper itself not read. M
  5. Six Sigma graduates receive Green Belt certification, Texas Children's Hospital news (2014). The article does not mention coaching. L
  6. Antony, Lizarelli & Fernandes, A global study into the reasons for Lean Six Sigma project failures, IEEE Transactions on Engineering Management 69(5) (2022). Expert opinion, not project counts. M
  7. Project failure: eight reasons (Minitab survey), iSixSigma, about 150 customers, undated. M
  8. Narottam, Mathiyazhagan & Kumar, common success factors of Lean Six Sigma, Int. J. Business Excellence 20(3) (2020). M
  9. Factors in Lean Six Sigma project success, 256 projects, IJMEMS 2(2) (2017). M
  10. Coaching packages: GoLeanSixSigma, sixsigma.nl, University at Buffalo. Public price lists, checked 22 October 2026. H

Public sources, no affiliation. These are other organisations' results, not Taktstone results and not typical outcomes. Found an error or a better study? Email hello@taktstone.com.