^ it's a chart published by billboard composed of 88 radio stations (for comparison, the Airplay chart monitors 144 radios in the US) and basically, as the name suggests, this Indicator Chart gives you week per week an idea of the next airplay #1, and with this week's chart we can see that radios think Carrie is heading for the top spot in the next weeks! Usually future Airplay #1s get to reach #1 on 'Country Indicator' a few weeks before topping the Airplay chart!
I hope i gave you a clear idea
