Home / Lean Six Sigma / Basic quality tools
Organize the team’s hypotheses about a problem into the 6Ms, see the fishbone drawn instantly, prioritize by votes and take the most likely causes to data-based verification.
Pre-sizing and estimating tool: results do not replace design, calculations or reports signed by a licensed professional, nor verification against the applicable codes and standards.
Drawn from the list: the bones adjust to the number and length of the causes. Circled numbers = priority order by votes.
Causes from most to least voted, with the cumulative percentage and the 80% line. Solid bars = highlighted on the diagram; grey = ruled out.
Where the team sees the problem: total votes per category and how many causes each received.
The same list as the diagram, ordered by votes, with the full path and status. Download as .xlsx for the verification plan.
Take this page’s results to another calculator with the fields already filled in.
The calculation report gathers this page's inputs, results, equations, assumptions and references, with fields for project, engineer and revision. The full report also includes the charts and interpretations, in color. In the print dialog, choose Save as PDF.
A cause-and-effect diagram shaped like a fish skeleton: the problem (effect) sits at the head and the possible causes are grouped into categories, the bones. Kaoru Ishikawa created it to organize team brainstorming and make sure no family of causes is forgotten.
The six classic categories for industrial processes: Manpower, Machine, Material, Method, Measurement and Mother nature (environment). In services and office processes, teams often use their own categories (policies, systems, customers). Here you can switch to 4M, 8M or create your own.
After brainstorming, each participant spreads 3 to 5 votes over the causes they think most likely. The total becomes the Pareto of causes: the few that gather 80% of the votes go to data-based verification first.
No. A vote only shows where to look first. A cause is confirmed when the data show the effect changes when it changes — for example, with a multi-vari chart, a stratified control chart or an A vs B test. Mark the status as confirmed or ruled out after verification.
After choosing a prioritized cause, ask “why?” in sequence until you reach something the company controls and can change: a standard, a system, a decision. If the last answer is “the operator made a mistake”, keep asking: why did the process allow the mistake?
Use the buttons below the drawing: PNG (image for presentations), SVG (vector for editing) or A4 landscape PDF (one-page report with the diagram, prioritized causes and 5 whys). On phones the drawing shows as a vertical tree, but the files always use the horizontal fishbone.
There is no right number, but a diagram with fewer than 8 to 10 causes or with empty categories usually means the problem was not explored enough. Specificity matters more than quantity: “insert changed by time, not part count” helps; “machine” does not.
Important notice: Indus Metrics tools produce estimates and pre-sizing results from the data you enter and from published engineering methods. They do not replace design, calculations or reports signed by a licensed professional engineer (PE), nor verification against the applicable codes, standards and regulations, such as OSHA rules and the ASME codes. Material and fuel properties vary: check manufacturer data or your own process analyses before deciding. By using this site you agree to the Terms of Use.
© 2026 Indus Metrics. Found an error? Write to contato@seudominio.com.