Most clients respond very positively to this initiative. And well they should. Better transparency of their marketing spend gives them a better handle on how to adjust it. Sales is the metric most often mentioned by clients. They want our work to affect their revenues. Makes sense. But when it comes down to committing to specifics, I've learned that few clients are willing to open their books with their agency, often because they feel it's confidential information.
That leaves the question: If measurement is so important, what should you and your client measure?
Satisfaction with how well you're servicing their business, for one. Creativity for another. Strategic thinking. Being proactive vs. saying you're going to be proactive. Accurate and timely billing. Managing the budget and not going over it. Eliminating surprises, by communicating early and often on all topics. Execution of ideas. Integration of disciplines. Number of media placements, if it's a PR relationship. Innovative use of media. Number of hits to a web site. And ease of use of the site. Or possibly even number of names captured in an online database that you've created for the client. You get the idea.
Measure the things that you can impact. And that mean something to your client.
Point is, there are so many "alternative" metrics you can use to measure your agency-client relationship, other than sales. So don't get tripped up on it if your client gets gun-shy about revealing sensitive financial information with your shop. It might be better anyway, since there are so many factors out of your control, when it comes to delivering sales. Try some of the ones I've mentioned above, and I bet you'll receive equally enthusiastic reactions from your clients when you bring up measurement.
The best reaction being renewal of your contract at the end of the year.