I've heard before that to estimate total radio ad revenues for a market, you take the market's retail sales and multiply it by 1/2 of one percent.
But, is that total retail sales including non-taxables such as groceries, or just taxable retail sales?
I thought the multiplier was .0004.
But either may still not be accurate. Local sales is usually calculated by local sales tax revenue #s and when someone in your market buys a pair of shoes online or out of market, that sale - which potentially could have been made at a local retail location - that is not included. The amount of retail done online or out of market cannot really be estimated in your market.
And - services are not taxed yet services are a growing category for radio. Medical services in particular.