Root Cause Analysis: 5 Whys, Fishbone, Pareto, 8D

Find out why a problem happened, and prove it: from the Pareto to a verified root cause, on one screen.

• Canvas: the fishbone, the 5 Whys ladder and the Pareto of one problem side by side and linked. The bar set as focus names the head of the fishbone; a cause selected on the fishbone opens its ladder.
• Fishbone in 6M, 4S or your own branches, drawn by the tool. Each cause is Suspected, Verified or Ruled out, with the evidence that decided it; causes ruled out stay visible, struck through.
• 5 Whys of two kinds, why it occurred and why it was not detected, with evidence on each answer, a read back with “therefore” and hints when the chain stops at a person, has no evidence or ends too early. A root cause counts only once verified with a method, evidence, a date and a person.
• Pareto from counts pasted from a spreadsheet: sorted bars, cumulative line, cut at 80 % by default, ties at the cut kept, Other row last, weighting, break down of a bar, before and after compared as rates. Ambiguous numbers are refused, never guessed.
• Quick analysis in four steps or full 8D, D0 to D8, switchable without losing data. The 8D report prints with the Pareto, the fishbone and the ladders inside; a summary on landscape A4; diagrams exported as PNG or SVG.
• Effectiveness check with method, result and evidence (10.2.1 d)); Not effective blocks the closure. Insights with the Pareto of verified root causes and a Lessons table, and a root cause summary for the management review.

ISO 9001 asks you to determine the causes of a nonconformity (10.2.1 b) 2)) and to analyse data (9.1.3); it names no method. The four methods are common practice, offered as one way to meet these clauses. Edition 2015 or 2026 in Settings; the English labels of the 2026 edition are a translation of the French text, and the tool says so.

Works with the Nonconformity & Corrective Action Log by typed references and a copy of the cause statement, so nothing is entered twice.

Works offline in Chrome, Edge or Firefox, on Mac and Windows. Stored in your browser only, with backup and restore, a demo company with 9 investigations, and a blank start.

You get the HTML file, the Quick Start Guide, a single-user licence for one computer and one year of support and updates.

199 USD lifetime licence, then 69 USD per year for updates and support. The price renews automatically each year at the renewal price shown at checkout. If you do not renew, you keep the tool; only support and updates stop.