[zenith]

In a nutshell you drink until you are caught by the cops for being drunk in public or have to go to the hospital. Your Blood Alcohol Content (BAC) is recorded at this time. You keep trying in hopes of getting a higher BAC. At the end of the day your highest BAC is how you are ranked.

You cannot lose your best rating, so it's to your benefit to try as much as possible. However, you might get a very high BAC early on and for the rest of the day never match it, while others might get terrible scores until the final seconds of the day.