think-five-whys
Five Whys
Five Whys traces a problem to a root cause by asking "why?" of each answer, about five times, until you reach a cause worth fixing. It is famous and frequently requested, and its evidence is weak: the critical literature finds it flattens multi-cause problems into a single chain and discards the rest. This skill runs Five Whys honestly. It leads with that caveat, then forces the one discipline a bare why-chain omits and that makes it safe to run at all: at each step, flag whether more than one cause could apply, and the moment the problem is multi-cause, say so and hand it to think-issue-tree. The output is a single linear why-chain with a branch-or-not flag on each step plus one countermeasure aimed at the terminal node, not a confident single root cause presented as the cause.
Before you run this: the evidence caveat
Five Whys is tier X (weak or contradictory evidence). The governing critique is Alan J. Card, "The problem with '5 whys'," BMJ Quality & Safety 26(8) (2017): 671-677, which argues the technique oversimplifies complex problems, follows a single causal chain when failures are multi-causal, and limits understanding of how processes actually fail; Card's prescription is to move to branching, systems-oriented causal-tree diagramming. John Allspaw, "The Infinite Hows (or, the Dangers of the Five Whys)" (2014), adds that in socio-technical systems the linear "why" chain drifts toward a person and a counterfactual (the "Bad Apple" blame trap) and recommends "how" over "why" to recover the multi-contributor picture. The method is reliable only for simple, linear, single-cause failures; beyond them its output looks like THE cause when it is one cause among many.
So a single chain is not a verdict. If you run Five Whys here, the value is not the chain, it is the discipline this skill adds: flagging at every step whether more than one cause could apply, and stopping to redirect when it can. For any problem that might have more than one cause - which is most real problems - think-issue-tree is the stronger move: it branches with MECE-plus-remainder discipline instead of forcing one path. Do not report a single root cause as the answer to a many-cause problem, and do not invent quantified claims about Five Whys' effectiveness (none are supported).
When to Use
- The user asks for Five Whys (or "5 whys") by name and you should run it honestly rather than refuse.
- The failure is plausibly a simple, linear, deterministic chain (a machine fault, a single procedural slip) and you will still flag any branch points you hit.
- As a fast teaching prompt for the habit of not stopping at the first explanation, with the multi-cause caveat attached.