This paper is an update of the Advertising Research Foundation's historic 1961 monograph "Toward Better Media Comparisons". It has been revised to include new levels of paid media performance attentiveness, persuasion and response and to consider new media types, especially online media and Interactive TV. The new model contains eight levels at which media performance can be measured to help marketers plan their advertising campaigns: vehicle distribution; vehicle exposure; advertising exposure; advertising attentiveness; advertising communication; advertising persuasion; advertising response; and sales response. The way advertisers think about media has changed in the last forty years. The Internet, Interactive TV and Direct Response advertising have expanded media's job from simply exposing a message to include encouraging and facilitating a response. The concept of recency has focused marketers on advertisingâs contribution to making the next sale. And more and more, it is on response that media are being judged. Media measurement has no choice but to follow mediaâs newly expanded purpose.