SigmaDesk · Fishbone Maker
Map your root causes
Add your effect, fill in the six M's, and get a clean Ishikawa diagram with AI cause suggestions — ready to track, export and share.
Built for Real Root Cause Analysis
SigmaDesk includes an online fishbone diagram generator — also called an Ishikawa diagram or cause-and-effect diagram — that lets you structure, analyze, and act on root cause investigations directly in your browser. It covers the full workflow quality practitioners use in the DMAIC Analyze phase, production quality reviews, and corrective action reports.
Six Standard Cause Categories
- People — training gaps, workload, skill level, operator variability, and other human factors behind the problem.
- Process — workflow steps, standard operating procedures, sequencing, and process controls that may be missing or inadequate.
- Materials — incoming material quality, supplier variation, storage conditions, and component specifications.
- Methods — work instructions, measurement and inspection criteria, and the decision rules the process relies on.
- Machine — equipment condition, calibration status, tooling wear, maintenance schedules, and mechanical capability.
- Environment — temperature, humidity, vibration, contamination, shift patterns, and other external conditions affecting output.
What the Module Does
A fishbone diagram is only as useful as the causes you put into it. SigmaDesk is built to make that part faster and more thorough.
Guided problem definition runs a structured setup form before you add any causes. You name the problem, add process context, select the department, set priority, define a timeline, and list stakeholders — so the cause-hunting session is specific rather than generic.
AI-powered cause suggestions are available per category. Click the AI button on any bone and SigmaDesk generates targeted suggestions from your problem description and process context — grounded in what you entered, not boilerplate. Review them, select what applies, and add with one click. A full pre-fill can also populate all six categories at once as a starting point.
AI problem enhancement sharpens vague problem statements before the session begins. If your description is rough, the tool rewrites it into a precise, structured statement that yields better suggestions and clearer diagrams.
Drag-and-drop reorganization lets you move causes between categories when one belongs elsewhere. Double-click any cause to edit it inline — no modal, no break in your flow.
Cause Analysis tab gives you a structured table of every cause across all six categories. Filter by category, impact, or investigation status, and update impact (Low / Medium / High) and status (Open / Under Investigation / Resolved) directly in the table — turning the diagram from a brainstorm into an actionable tracker.
Excel export packages the full analysis — problem statement, causes by category, impact ratings, and statuses — into a formatted spreadsheet you can attach to a CAPA report, an 8D, or a DMAIC project folder.
Frequently Asked Questions
What is a fishbone diagram used for?
A fishbone diagram is used to identify and organize the potential root causes of a specific problem before you try to fix it. As one of the seven basic quality tools, it sorts causes into categories so a team brainstorms systematically instead of jumping to conclusions, and it pairs naturally with a histogram once you move from finding causes to verifying them with data. It is a core tool in the Analyze phase of DMAIC.
What are the 6 M's in a fishbone diagram?
The classic 6 M's are Man (People), Machine, Method, Material, Measurement, and Mother Nature (Environment). SigmaDesk uses six equivalent categories — People, Process, Materials, Methods, Machine, and Environment — so every major source of variation gets its own branch. The exact labels matter less than covering all six domains so no cause is overlooked.
Is there a free AI fishbone diagram maker?
Yes — SigmaDesk offers a free, browser-based AI fishbone diagram maker with no installation. It suggests causes per category from your problem description, lets you rate and track each cause, and exports the finished analysis to Excel.
What is the difference between a fishbone diagram and the 5 Whys?
A fishbone diagram maps the breadth of possible causes across categories, while the 5 Whys drills into the depth of a single cause chain. They work best together: use the fishbone to surface candidate causes, then apply the 5 Whys to the most likely ones. Once you confirm a cause, verify the fix with data using a control chart or a process capability analysis.
After the Fishbone
A fishbone surfaces candidate causes; data confirms them. Once you have narrowed the list, verify the fix with a control chart to confirm the process is stable, then a process capability analysis to confirm it meets specification. If the measurement itself is in question, start with a Gage R&R study — an unreliable gage will send a root cause investigation in the wrong direction entirely.
Start your root cause analysis
Create a free account to build Ishikawa diagrams, get AI cause suggestions grounded in your problem description, track every cause to resolution, and export the analysis to Excel.