Crossword blog: what makes a puzzle 'difficult'?

One index of a crossword’s ‘difficulty’ is how long it takes us to solve it. Is it the only measure?What is “difficulty” when it comes to solving a crossword?First, a happy thought. I sometimes mention a poll I commissioned, which suggested that, in the UK, over 7 million people decide which paper to buy at least in part on the basis of the crossword. I mention this, of course, because America’s free press is being intimidated, and so it needs money. What I&rs