In the academic journal article "The Role of Deliberate Practice in Chess Expertise" from APPLIED COGNITIVE PSYCHOLOGY Appl. Cognit. Psychol. 19: 151– 165 (2005) http://www.psych.utoronto.ca/users/reingold/publications/PDFs/Charness.Tuffiash.KrampeAPPLIED COGNITIVE PSYCHOLOGY Appl.Krampe Cognit.Vasyukova Psychol. 19: 151– 165 (2005.pdf) ,at
At the top of page 162, the authors state that
"...each log unit of serious study alone yields about 200 rating points compared to 33 rating points for log tournament play. Hence, players ought to devote the majority of their time to that activity."
I have gone over this academic paper several times, but I cannot decipher what "each log unit" represents. What time span is a "log unit" in this context where studying chess alone gave the chess players in this academic paper 200 ratings points vs 33 ratings points from playing in tournaments? Is it 6 months, 10 months, a year?