http://www.moneycafe.com/content/articles/9/1/Certificates-of-Deposit-Index-CODI/Page1.html

Published on 03/12/2007

This index is the 12 month average of the monthly average yields of 3 month certificates of deposit. In plain English, this index is calculated by averaging the previous 12 rates of the 3 month CD rate. The 3 month CD rate used is the rate publish monthly by the Federal Reserve. Because this particular index is an annual average, it is more steady than straight CD rates.