I usually hear people (e.g., Jerry Briesath) say that the main cause of a miss is a poor stroke or poor cueing, even though the shooter may think that they aimed poorly. I believed this when I first heard it, but I've started to wonder.
My percentage for straight-in shots, even long ones, is much higher than my percentage for cut shots of the same length. That's aim, not stroke.
I'm curious about other pool players: Do you think you miss more because of poor aim, or poor stroke?
Back to the original question,
I think it depends on the circumstances surrounding that particular miss. For example: A few years ago, Jack Nicklaus was interviewed at the Masters. The interviewer asked: What happens to a player who is moving right along in a tournament and suddenly starts hitting bad shots? What's going on?
Nicklaus's answer was, Usually in competition, it's the swing timing that goes off and then the player has to find a way to get it back.
So, what are the circumstances of your miss?
Are you in competition?
Are you practicing the same shot over and over and missing it each time?
Are you getting hungry or tired?
Are you playing against a friend and talking a lot?
Have you been in a slump?
Do you miss shots in that direction a lot?
Have you recently made a change in your fundamentals?
Were you trying to apply side spin?
Were you trying to move the cue ball in an unusual way?
Each one of these could have a different answer as to why the player missed.