Puzzle "difficulty" score?

Sort:
Avatar of TripleArray

What does this "Difficulty" score mean? This is on the mobile app and it only appears after I have solved a puzzle and view it again (from my Stats screen). It is not the puzzle rating (which is 1525 in this case), and it is not my own puzzle rating. It seems like this number can vary a lot, even for puzzles with similar ratings. TIA!