The question of how to provide a meaningful evaluation of PR campaigns is one that I've never seen successfully resolved.
There are many tools and measures touted around which claim to offer a definitive answer to this sticky problem. But is reducing column inches to a sheet of statistics any more helpful than just feeling the weight of the cuttings? It certainly gives the veneer of science to the results – although for my money this can be just as baffling.
AVEs or advertising value equivalents, are another simpler approach which measures the size of the clipping, values in it in terms of how much it would cost to buy advertising for the equivalent page space and then multiplies that value, typically by three to allow for the extra value of ‘independent’ endorsement. This can be run alongside competitor evaluations to give a more rounded market picture. Whilst that does give more than a finger in the air, unless it’s aligned to campaign objectives, it can still be fairly meaningless. There’s no point in claiming a value of £2,000 for a page of editorial in Bee Keepers Quarterly if you’re targeting fish farmers as the chance of it actually reaching buyers is negligible.
The true answer is in to evaluate perception change among customers through independent, aligned to a clear set of objectives. Yes, this costs money, however if a true proof of results is required it’s not about looking at the outputs in isolation, but looking at who those outputs reached. Where boardrooms can quibble about whether X in press coverage truly does equal Y in monetary terms, there’s no arguing with a sample set of 100 potential customers whose awareness of the brand and its messages has increased by x% over a given period.
The key is to clearly define objectives, markets and desired outcomes from the very beginning, and responsibilities on both sides of client/agency relationship for achieving these. After all, if you don’t know what you’re measuring, you’re never going to know how big it is.