ROS (Run of Schedule / Run of Station)

ROS buys let the station decide placement: within broad constraints: and in exchange offer a substantial discount compared to fixed-daypart rates. A 50-spot ROS buy might distribute across morning, midday, afternoon, evening, and weekend slots in whatever mix best fits the station's remaining inventory.

ROS is the quintessential reach-and-frequency buy. It delivers mass Cume because spots hit every audience segment the station serves, and frequency because the spot count is usually high. The weakness is lack of targeting: a luxury advertiser who only needs to reach affluent commuters is wasting impressions on overnight listeners. ROS is therefore best for broad-appeal products and promotional messaging with universal relevance.