Here's How We Made Business Insider's Hangover Index

Since it's New Year's Day, we found the 25 American cities most likely to be hungover today, based on a few indicators that suggest heavy drinking activity.

Our two main sources were the CDC's 2011 Behavioural Risk Factor Surveillance System (BRFSS), an annual survey of Americans' health habits, and the Census Bureau's 2012 County Business Patterns (CBP) program, which tracks the number and size of businesses in counties and metropolitan areas across the country.

We used five total indicators from these data sets to construct our ranking:

• Binge drinking: The percentage of respondents in a metropolitan area who said they had binge drunk in the last month on the BRFSS survey. The survey defines binge drinking for men as having drunk 5 or more drinks on a single occasion, and for women as having had 4 or more drinks on a single occasion.
• Heavy drinking: The percentage of respondents who said they were heavy drinkers on the BRFSS survey. The survey defines heavy drinking for men as having, on average, two or more drinks per day and for women as having, on average, one or more drink per day.
• Number of bars per 100,000 residents: The number of drinking places primarily dedicated to serving alcohol in each metro area, according to the 2012 CBP. This category, and the other establishment-based metrics below, is adjusted by the Census Bureau's estimates of the 2012 population of each metro area to account for the variation in size of America's cities.
• Number of beer, liquor, or wine stores per 100,000 residents: The population-adjusted number of retail stores selling alcoholic beverages for home consumption, from the 2012 CBP.
• Number of alcoholic beverage producing establishments per 100,000 residents: The population-adjusted combined number of breweries, wineries, and distilleries in the metro area, from the 2012 CBP

BRFSS data were available for 168 metropolitan areas and divisions with at least 50,000 residents, and so these were the cities we ranked. The metro areas were percentile ranked in each of the five variables listed above, and to get our final Hangover Index, we averaged those ranks together, giving each city a score with a theoretical range of 0 to 99.