Moody’s Investor Services uses a unique rating scale, running from a high of Aaa to a low of C, to determine the Bond Rating for each city and county in the country. The rating scale is then divided into two sections, investment grade and speculative grade. The rating is Moody’s opinion of the credit quality of individual obligations or of an issuer’s general creditworthiness and it can change at any time throughout the year. Pittsburgh Today created its Regional Bond Rating Index based on Moody’s most current bond ratings for our benchmark cities and their corresponding counties. Using a score ranging from 20 (Aaa rating) to 0 (C rating), we then combined the individual scores allocated to our benchmark cities and their corresponding counties to achieve a regional score that was then used to rank the benchmark regions from highest to lowest.