BDI and CDI Research Guide 

Definition: "The BDI is a measure of the relative sales strength of a given brand in a specific market area of the United States."

To calculate: "Divide the percent of brand A's total U.S. sales in market X by the percent of the total U.S. population in market X, then multiply the result by 100 to get the index number."

"It is especially useful, along with the Category Development Index (CDI), in deciding media allocations and how much advertising or other promotion effort to put in different market areas."

(The above from Professor Govoni's website).

To find out your product's brand sales in a specific geographic region you may have to make some educated assumptions after looking at the following resources:

Use these resources to find the projected number of people who use your product.