1999 by Jan S. Gephardt. They stay in business longer, make considerably more money, and experience fewer internal conflicts than businesses without a written plan. There seem to be many reasons, though none are good. This used to be my excuse. It's an excellent way to lose your direction and fall into the habit of doing what's handiest, instead of doing what pays best or is what you'd really like to do most.
Planning is just busywork.
In light of the study results, apparently not. Henry Ford observed that many people will do anything to avoid the hard work of thinking. I have a plan. It's just not written down. This rarely works for real people with average memories.