Abstract: A method and system for determining a probability that a media display will be observed. The method comprises accessing a circulation quantity, which is a function of traffic volume through an associated geographic area. An opportunity quantity is calculated as a function of the circulation quantity. A likely-to-see quantity is calculated by multiplying the opportunity quantity by a predetermined coefficient. A probability that a media display will be seen is calculated by adjusting the likely-to-see-quantity by demographic data. The calculation may also use an extrapolation algorithm to determine the probability.