I'm asking this because I've never heard of it happening with any radio station in any market I've lived in since the technology existed. Are there any radio stations that have "member" cards of any sort that have a scannable bar code on the card that can be scanned at a store check-out register? I'm aware of using special 800 number extensions to track responses for businesses that want to track phone responses. I'm talking about something similar, but different. I'm talking about tracing an actual sale of a product directly to a listener's station membership card at the time of purchase.
Theoretically, if you were part of a smaller market setting, and could get your listeners to participate, it could work. However, these days many advertisers are not getting their moneys worth out of their investment.
I'd really like to see it tested though! It seems like a cool theory (and if the advertising was working, it might lead to some real benefits). My only concern is that some of the advertisers will become aware that their ad is useless.
That's why I included the other aspect of the test. The advertiser would pay the station commission based on the dollar volume of trackable purchases. If there are no purchases tracked back to the scanned card, the ad would cost the advertiser nothing. But if the ad is a whopping success, with lots of tracked purchase volume, then the station would earn a healthy commission. It could help smaller market convince advertisers who are skeptical to give radio advertising a try.
For example, a local grocery store might advertise a special discounted price for all listeners of a given station on a certain popular commodity, like the store's house brand of charcoal right before a major local sporting event that has lots of tail-gating. Station listeners would already have cards because the store would have promoted them in advance for discount tickets to concerts or other station-sponsored events. If loyal listeners used their station cards to buy the store's house brand charcoal, the store would have stats captured on how many customers used the station's card, how much charcoal they bought, how much additional merchandise they bought on the same shopping trip, and whether or not the customer also had the store's loyalty card or not. That latter would tell how many new customers they attracted.
That's a risk for the station, since it might demonstrate that ads on their station don't work. Then again, in this scenario we're talking about a grocery store or chain that usually doesn't buy ads at all, so worst case for the station is that they gave away some spare airtime. Best case, they prove that their ads are worth buying, so they get repeat business.