I recently enabled this option inside MS Word's spelling and grammar check. It's an amusing metric that measures the approximately minimal reading comprehension ability needed to understand a certain passage of text.
So my entry about Copenhagen the play has an index of about 11, which means that an average 11th grader (high school junior) should be able to understand it. This somewhat abstruse entry from Fractal Ontology has an index of about 19. That probably requires one of those liberal arts college education hmm (and a real Ph.D., i.e. in philosophy while at it)
I think one example where this test wouldn't be accurate might be something like "The dog barks arf-arf-arf-arf-arf-arf-arf-arf-arf-arf-arf-arf-arf-arf-arf-arf and the cat goes meow-meow-meow-meow-meow-meow-meow-meow-meow-meow-meow-meow-meow-meow-meow." This has a score of 38 according to this calculator. Which would mean that one needs to complete 38 years of schooling to understand that, oops. Perhaps a heuristic that breaks up hyphenated words might be helpful here.
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