I keep thinking of the quote ‘tanquam ex ungue leonem’, commonly translated as ‘you will know the lion by his claw’.
It means that you will recognise the relative skill of a person by the quality of their work, assuming you have some expertise.
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John Bernoulli was said to have uttered it when he examined a paper written by a young Newton.
But there’s also an interesting inverted application: when an expert reads something and scrunches up their face in disgust, you might want to probe further.