The traditional method of measuring PR (pioneered by Dr Walt Lindenmann) was via the measures of Output, Out-take and Outcome. They have been widely covered in academic journals and used as a method of categorising response measurement. Dr Tom Watson in DummySpit outlines their use in this useful review. But there seems to be a problem as the ‘Outs’ are often misused and I think it is fair to say, poorly understood by practitioners.
So in response a couple of alternatives have been pitched. Dan Bartholomew suggests the Exposure, Influence and Action categories, while Jim Nail suggests Media Influence, Media Audience and Business Influence. They both undoubtedly have their merits and while I think they could be accused of introducing more jargon, discussion on this issue is healthy, particularly if it engages view from the wider PR community rather than from just within the measurement community.
Personally I prefer Dan Bartholomews option but as this is very early days much more information and practical application and testing needs to be done. And of course if a new option is to be adopted it needs to be much better than the existing.