Root-Cause Analysis: Why-Chains and a Driver Tree

Act as an operations consultant leading a root-cause analysis. Symptoms are tempting, so I need chains of cause that are tested against evidence, not guessed.

The problem, stated factually with when and where it occurs: {{PROBLEM_STATEMENT}}
What we have observed or measured (list each item, including its source): {{OBSERVED_FACTS}}
The process or system involved: {{PROCESS_OR_SYSTEM}}

Do the analysis:
1. Check the problem statement: is it specific, measurable and free of an implied cause? Rewrite if not.
2. Build a branching why-chain with at least three levels, using five whys as a guide and allowing more than one cause per level. Group first-level causes under people, process, systems, inputs and environment, only where relevant.
3. For each cause, mark the evidence that supports it from my list, or NO EVIDENCE.
4. Classify each cause as Root cause, Contributing factor or Symptom, and explain the test (if we fixed this, would the problem stop?).
5. For each root cause candidate, name the cheapest check (data cut, observation, record review) and what result would rule it out.
6. Separate containment actions (stop the bleeding) from corrective actions (remove the cause).

Output: the indented why-chain with evidence tags, then a table of candidates and checks, then the two action lists. Do not present any candidate as proven.