Work out pareto contribution instantly with clear inputs, formula shown and shareable results.
Pareto analysis ranks categories by frequency and reads the cumulative share, looking for the vital few that account for most of the problem. When two of four categories carry 70-80% of occurrences, effort concentrated there returns far more than spreading it evenly.
Pareto share
Category share % = category count x 100 / total; cumulative share adds ranked categories in order
Cost or impact, wherever it can be estimated. A frequent trivial defect can rank above a rare catastrophic one on count alone, which sends improvement effort to the wrong place.
Then there is no vital few, and the categorisation is probably too coarse or too fine. Re-stratify by a different factor — machine, shift, material lot — until a pattern emerges.