Concept
Five Whys
The Five Whys is a root-cause method that Eric Ries borrowed from Toyota: a team asks "why?" about a problem five times in a row to get past the human error to the process that allowed it, then makes a fix at every level in proportion to the harm caused.
Speed has a price. The more experiments and releases you run, the more often something breaks. The real question is whether each break leaves the team wiser or just more nervous. The first answer to "why did this happen?" is almost always a person: someone pushed the wrong button. If you stop there, you get blame, and blame teaches people to hide problems. If you keep asking, the trail leads to training, tooling, or a decision nobody remembers making. Ries adds a rule called proportional investment. A minor glitch earns small fixes at each layer, and a serious outage earns bigger ones. This keeps the method from becoming a ritual that changes nothing, or an excuse to rebuild everything. Five is a guide, not a law. Stop when you reach a cause you can actually change. The working assumption is simple: if a mistake was easy to make, the system made it easy.
A real-life example
A small online shop sends 40 customers the wrong discount code. Why? The new hire typed the code by hand. Why? There was no template. Why? The founder kept the campaign steps in her head. Why? Writing them down never felt urgent. The fixes are to correct the 40 orders and apologize, add a two-line checklist, run a 20-minute training, and block one hour a week for documenting processes. Nobody gets blamed.
How to use it
- 1Write the problem as one concrete sentence. Invite everyone involved to the session, including the person who made the error.
- 2Ask "why?" of each answer in turn. When you reach a person, keep going and look for the process that let them make the mistake.
- 3Assign one fix per layer, sized to the harm, with an owner and a date. Use small steps for small problems and bigger ones for serious problems.