Brand valuation experts place a high premium on internationality. David Andrew in Interbrand's publication Brand Valuation says: "Brands which have proven international acceptance and appeal are inherently stronger than national or regional brands". In Interbrand's brand valuation system, the 'internationality' dimension carries 25% of the total score, equal first with 'leadership'.

Global marketing companies know this and put vast resources behind promoting their brands across the continents. The advertising industry is dominated by groups of agencies who have opened offices in hundreds of countries to serve their clients.

So do clients and agencies manage their campaigns like a well-oiled machine? Well - in our experience anyway - no. As consultants, we observe and analyse many global relationships. Let's be fair and acknowledge that we are usually called in when things are less than hunky dory, and often in new relationships where problems have struck early. Here's what we tend to find:

* Dissatisfied central clients, criticising their agency for having exceeded budget, being behind schedule and infuriating their colleagues. Above all, the promise of famous creative work (which settled the outcome of the pitch in favour of the chosen agency) has not been realised.

* Frustrated agencies, claiming to be losing money. They are not working well with the HQ clients and are starting to fall out with their colleagues around the world. These local agency managements much prefer dealing with national clients, who are easier to work with, far more likely to provide opportunities to fill the shop window and win awards, and are seen as more profitable.

So what has gone wrong? It can be weaknesses in the people on both sides - lack of experience, lack of chemistry, and sometimes sadly simply lack of ability. We believe that the real problem is that having been rigorous decision takers during the agency selection process, clients frequently take their eye off the ball once the new relationship is under way. Let's take a couple of examples of invalid assumptions in the world of international advertising:

* "There should be a brand proposition that works everywhere, so the agency can develop an international campaign"

* "They are a famous international agency, so they know best"

The potential decision traps here are: first, trusting the agency to know what development process to follow, and second, believing what you want to believe - our brand is sold in 37 countries, therefore it should have a global campaign. Before you know where you are, six months will have passed, the agency will have spent most time on "strategic development", the planners will have passed the baton to the creatives, and you will be looking at six routes - all in English naturally - to go into research. None of them have set the Thames alight. There are also doubts about whether the Yangtse will be set alight either, given the awkwardness about the Chinese not having heard of John Cleese. Timeburn on your (as yet unsigned) resource package agreement will already be massive, as will the travel bill. Yet some other key decisions will not have been made - or if they have been, probably not fully shared with the agency:

* Short, medium and long term commercial objectives - globally, by region and by market?

* Which markets will have advertising this year? Next?

* Detailed levels of budget and media spend by market?

* Media selection?

If this in any way sounds familiar, you would probably benefit from the proprietary five stage sequential decision pathway we have developed for our international clients called DISCO.

D is for Deliverables. Before we look at how our international advertising might look and sound, what is it for? What results is it supposed to achieve? Over what time frame? How will it fit with the rest of the marketing mix? Responsibility: client marketing team. No agency - however brilliant - can make much contribution until the client has thrashed this out.

I is for Investment. How much can we afford to invest to hit those targets? What do we need to budget for media, production and agency fees? Responsibility: led by marketing accountants with significant upfront inputs from the media agency.

S is for Strategy. Spend time on marketing and communications strategy, looking in depth at the brand and digging for insights to inspire the creative process. Responsibility: led by brand specialists in the client marketing team, working closely with agency planners.

C is for Creative. The agency at last comes into its own, but it should be looking at far more than just ads in English. Responsibility: led by the central agency creatives and planners, but involving colleagues from all key geographies and markets.

O is for Operations. Client team: how are we going to manage our international campaign? Agency team: how are we going to resource and operate? Drivers: effectiveness, efficiencies, value. Need to tailor, design, cost and agree an operating system to deliver whatever advertising and marcoms the brand needs. Responsibility: led by central client and agency teams, working together.

DISCO is nothing more than logic and common sense - but as a framework for taking the key decisions in an endeavour as fraught and risky as international advertising, it is a better bet than winging it.

David Wethey is chairman of Agency Assessments International, which advises clients on selecting new agencies and getting value out of existing partnerships.