The free SimplicityHub® Root Cause Analysis course. Learn the proven tools that uncover what’s really going wrong — and fix it for good. No card needed.
A quick look at the free Root Cause Analysis course — what you'll learn, and why it's genuinely free.
Nine practical skills you can use on any problem, in any industry — from manufacturing to healthcare to the office.
Why most fixes fail — and what RCA does differently.
Root cause analysis (RCA) is a structured way of finding the deepest reason a problem happens — the cause that, if removed, stops it coming back. Most teams are brilliant at firefighting: see a problem, apply a quick fix, move on. But treat only the symptom and the problem returns in a new disguise. RCA breaks that cycle by forcing you to keep asking “why” until you reach something you can actually change. It sits at the heart of continuous improvement and DMAIC.
Every problem has three layers. The symptom is what you notice. The cause is the immediate thing that produced it. The root cause is the deeper condition that allowed that cause to exist. Fix only the symptom and you’ll be back tomorrow. Spotting which layer you’re looking at is the single most important RCA skill.
RCA takes time and people, so use it well. Run it when a problem is recurring, costly, safety-related, or genuinely puzzling. For a one-off trivial glitch, a quick fix is fine. Rule of thumb: if it’s happened more than once, or the cost of it happening again is high, it’s worth a proper RCA.
The fastest way to kill an RCA is to make it about who rather than what. The moment people fear blame, evidence dries up. Good RCA is blameless: it assumes people acted reasonably given the system and information they had, and hunts for the process weakness. Watch for bias too — jumping to a favourite conclusion, or seeing only confirming evidence.
Q1. A ‘root cause’ is best described as:
Q2. A blameless RCA culture matters because:
You can't find the cause of a problem you haven't defined.
A strong problem statement is specific, measurable and free of assumed causes or solutions. It answers what is happening, where, when and how big — and deliberately avoids saying why (that’s the investigation’s job). A vague statement sends a team in ten directions; a sharp one focuses everyone.
Is/Is-Not boxes a problem in. You list what the problem IS affecting alongside what it could be but ISN’T. The contrast points straight at what’s different — and difference is where causes hide.
Most problems have a ‘first time it appeared’ moment. Laying events on a timeline reveals what changed just before it started — a new supplier, a software update, a staff change. Change is the usual trigger, and a timeline makes it visible.
Before hunting causes, agree what ‘solved’ looks like and how you’ll measure it. A clear target keeps the RCA honest and tells you when to stop. Tie it to the same metric in your problem statement so improvement is undeniable.
Q1. A good problem statement should NOT include:
Q2. Is/Is-Not analysis helps you:
Facts before theories.
Before theorising, collect facts from five sources: People (what those involved observed), Parts (the physical items or outputs), Paper/Position (records, logs, settings), Paradigms (assumptions and “we’ve always done it this way”), and Data (measurements and trends). Gathering across all five stops you fixating on the first clue.
Evidence is only useful if it’s clean. Avoid leading questions, hearsay and recency bias (assuming the newest change is always the cause). Where you can, go and see for yourself — the Gemba principle — because second-hand descriptions lose the detail that cracks the case.
A data-collection plan decides what you’ll measure, how, who collects it and when — before you start. It stops you drowning in random data and ensures what you gather is comparable and reliable.
The Pareto principle says roughly 80% of problems come from 20% of causes. A Pareto chart ranks causes by frequency so you focus on the ‘vital few’ rather than the ‘trivial many’. It’s the fastest way to know where to aim.
Q1. The Pareto principle suggests:
Q2. Going to see the problem yourself (Gemba) helps because:
The toolkit — and how to choose.
The 5 Whys is the simplest RCA tool: ask “why?” repeatedly — usually about five times — until you reach a cause you can act on. Its power is simplicity; its danger is stopping too early or following a single track. Always check each “why” genuinely causes the one above it.
When a problem could have many causes, the Fishbone diagram organises a team brainstorm into categories — classically the 6 Ms: Man, Machine, Method, Material, Measurement and Mother Nature (environment). It structures the search so no category is forgotten.
Fault Tree Analysis is a top-down logic diagram that starts with the failure at the top and branches down through the conditions that could cause it, using AND/OR gates. It shines for complex or safety-critical failures where several things must line up.
FMEA is preventive: list the ways a process could fail (failure modes) and score each on Severity × Occurrence × Detection to get a Risk Priority Number (RPN). The highest RPNs get attention first. It’s RCA turned forward — stopping problems before they happen.
You don’t need every tool every time. Simple, linear problem → 5 Whys; many possible causes → Fishbone; complex logic or safety → Fault Tree; risk and prevention → FMEA. Often you’ll combine them — brainstorm with a Fishbone, then drill the top branch with 5 Whys.
Q1. Which tool is best for a complex, safety-critical failure with combined conditions?
Q2. In FMEA, the Risk Priority Number (RPN) is:
Q3. The main risk of the 5 Whys is:
Proving the cause and fixing it for good.
A suspected cause is a hypothesis, not a fact. Before spending money, prove it — ideally by turning it ‘on and off’ and watching the problem follow. Remember correlation isn’t causation. A cause-validation matrix helps you weigh evidence for and against each candidate.
There are two kinds of fix. Corrective action stops the current problem (contain the damage now). Preventive action stops it ever happening again (fix the system). Great RCA reaches for the preventive fix — containment alone just buys time.
You’ll usually have several possible fixes. Rank them on impact vs effort: quick wins (high impact, low effort) first; big projects planned properly; low-impact ideas parked. This stops you pouring effort into a fix that barely moves the needle.
A solution isn’t real until it has an owner, an action and a date. Write it down, assign accountability, and decide how you’ll test it on a small scale before rolling out everywhere. A pilot catches side-effects cheaply.
Q1. Before designing a solution, you should first:
Q2. A preventive action differs from a corrective action because it:
Making sure it stays fixed.
After implementing, measure again and compare to your baseline. Did the metric from your problem statement improve? A before-and-after comparison turns “I think it’s better” into proof — and if it didn’t improve, you’ve learned your suspected cause was wrong, which is valuable too.
Improvements fade without control. Lock in the gain with standard work (update the procedure), ongoing monitoring and clear ownership. A sustainability plan names who watches the metric, how often, and what triggers action if it slips.
Stakeholders want a page, not a novel. A good RCA summary states the problem, the root cause found, the evidence, the action taken and the result. It makes your work credible and repeatable.
The final step is cultural: make structured problem-solving the default, not a special event. Keep a lessons-learned log so the organisation remembers, and celebrate causes found — not blame assigned. From here, your natural next step is a full Green Belt to master the wider DMAIC toolkit.
Q1. You verify a fix worked by:
Q2. Improvements fade over time unless you:
Complete all six modules, then take the 20-question final exam. Score 70%+ and your free SimplicityHub® certificate is issued instantly — unlimited retakes, no payment, ever. If it says free, it’s free.
Yes — completely. The course and the certificate are 100% free. No card, no upsell, no catch.
No. It’s designed for beginners through to intermediate. It sits naturally between White Belt and Green Belt but stands on its own.
About 4–5 hours at your own pace, across 6 modules and 24 lessons.
Yes. Pass the final exam (70%+, unlimited retakes) and your free SimplicityHub® certificate is issued automatically.
Once you’ve mastered RCA, the full Green Belt course builds on it with the wider DMAIC toolkit.
