I don't have any hard data, but I feel better and seem to have a better grip on life since I started. I'm using a relaxed version of Bullet Journal and I kept at it for much longer than I expected.
Seconded. I put a recurring event called "Articulation" into my calendar, 30 mins each evening.
Sticking to jotting down my thoughts for the day, having to explicitly organize and summarize them (work, personal, whatever), has been an unexpected boost to clarity.
And this despite being in a managerial position, where you could say my days are filled with talking, organizing, resolution and strive for clarity anyway. The "self-articulation diary" still pays off.
I started using my planner to also write notes on what I did that day and any thoughts I had. I now feel more like I know myself and my organisational skills have improved.
I don't have any hard data, but I feel better and seem to have a better grip on life since I started. I'm using a relaxed version of Bullet Journal and I kept at it for much longer than I expected.