From 50/50 (it could swing either way and you can have zero knowledge on which way it'll swing), to %1-100 being able to know before hand, how much can you know?

What causes prices to go up? What causes them to go down? Obviously, no one knows for certain when it would happened, but has there been a consistent "pattern" lately? When prices have gone down, have you known to a reasonable degree than they would bounce back up? How?