Years of painful experience have taught me that no matter how we strive to be fair, to be objective and to be constructive, there will be agencies who disagree with our assessments.
The truth is that these reports matter. They matter to staff, to clients, to potential staff and potential clients, and they matter to network chiefs and holding company bosses keen to get our perspective on how their UK assets are doing. The fact that it matters so much is something we're very proud of, but it's also exactly why compiling the report is such a painstaking and lengthy process.
And as billings have become only a partial indicator of an agency's health, our own assessments on business development, management strength, innovation and work have become even more pertinent, filling the quantitative vacuum with a careful qualitative assessment.
Of course, if Sarbanes-Oxley is ever relaxed (and there are rumblings in the US that it will be), perhaps we can start to overlay the relatively crude billings figures with income data once again and get closer to a real understanding of agency financial health.
Right now, though, I'm not sure whether either billings or income would suffice as a barometer of agency heartiness. Last year's figures are scant indication of whether an agency is emotionally and physically equipped for the future. Being able to decipher how well a chief executive is really prepared to take their agency forward over the next five years, how committed a creative director really is to embracing digital, or how strong inter-group relationships really are when it comes to delivering integrated ideas are far more useful indicators in determining which agencies are likely to survive the next few years (relatively) unscathed.
It's against these measures that advertisers need to judge whether an agency is right for them, or staff to decide whether they have a long-term future in their agency. And it's against these measures that analysts are increasingly rating agency stock.
Having said all of that, the billings figures for 2006 do present a fascinating picture of an agency marketplace in turmoil. The traditional markers, the old benchmarks of agency stature, are breaking down and for those agencies used to surviving on the strength and depth of their agency machine (rather than, say, the soaring brilliance of their ideas), the figures are exposing. The best agencies will see this as liberating; size is no longer a guarantee of very much at all.
When I first heard the news that Lee Daley was leaving Saatchi & Saatchi, my reaction was that he was bailing out before his job there was complete. Saatchi & Saatchi is certainly not an advertising agency firing on all cylinders.
There have been no real creative highlights (aside, perhaps, from last year's Carling World Cup spot "Old Lions") and the mainstream new-business machine has been sluggish. And dropping out of the Top Ten this week is a significant emotional blow.
But on many of the measures discussed elsewhere in this column, Daley has revolutionised the company in the two years since his arrival. The launch of the branded entertainment division Gum, of the research and development lab Industry@Saatchi and the digital sensibility that seems to run through much of the company are all signs that the agency is well placed to ride the wave of change washing over the industry. By all accounts the bottom line is looking much more robust, too.
The Saatchis machine has been dragged 360 degrees to face the digital future in far fitter shape than many of its direct competitors. The real challenge now will be finding someone with Daley's energy and passion to keep up the momentum.