Looking at OOH as narrow-casting

Likewise, the clarity with which a radio ad is heard on SAfm in Polokwane, will generally be similar in quality to how it is heard in Port Elizabeth.

Different challenges

The net effect is that monitoring a single source (a copy of the magazine or a single recording of the radio ad) gives you relative comfort that your message has been delivered uniformly across your intended audience and, all things being equal, your adspend has done its job. That is the power of broadcasting!

Outdoor media presents a whole different set of challenges in monitoring your return on investment, as campaigns can be classified as a group of 'narrow-cast' media, with each medium having unique delivery capabilities.

On a billboard campaign for example, one board's visibility time may not allow for the reader to get the full message, while another's impact is reduced by visual clutter. One may have brilliant elevation and visibility delivering the message in its full glory, while another has an obstruction blocking the number to SMS.

Unique narrow-caster

In essence, single source monitoring does not provide any comfort that your message is being delivered the way it was intended. Of course one could argue that a few copies of a publication will be spoilt by the time they reach the reader.

In all probability, those few spoilt copies do not have a material impact on the return you will get on the advert while even one misplaced message on a billboard at a cost more than R20,000 certainly will.

The cornerstone to effectively monitoring and evaluating outdoor media placement is to treat each site as a unique 'narrow-caster' and evaluate it on its individual merits.