[hafabnew]

Neat!

From their JS:

  readinglvl = getReadingLevel(paragraphs, sentences, words, chars);
  [..]
  function getReadingLevel (p, s, w, c) {
      var r = Math.round((4.75 * (c / w)) + (0.5 * (w / s)) - 21.43);
      return r;
  }

So it's a slightly modified http://en.wikipedia.org/wiki/Automated_Readability_Index (uses 4.75 instead of 4.71 .

[adam_b_long]

That's right. We're using ARI, mainly because it's a much simpler algorithm since it doesn't require identifying syllables. As you can see in the code, my programming skills are pretty weak, so ARI was an easy choice. This was my first non-trivial programming effort (I'm a marketer/product manager, not an engineer).

[hafabnew]

Was not meaning my comment as a slight to you at all, it's a very cool app you've got here. Best of luck with it!