The International Olympic Committee (IOC) are always very keen to emphasise that the Evaluation Commission Report they release a month ahead of the final vote to decide a Host City does not try to rank or categorise the candidates.

And every time they publish the Report the bidding cities and the media try to work out in which order the IOC has ranked them.
 

Nothing had changed yesterday when the IOC published its Evaluation Commission Report for the 2016 Games and Olympic-watchers like me came up with our own unofficial rankings list.
 
That is why in Rio de Janeiro last night the campaign leaders, if not quite cracking open the champagne, were probably at least allowing themselves a couple of caipirinhas to celebrate an overwhelmingly positive report, while in Tokyo and Madrid they were drowning their sorrows with a glass of Saki and rioja respectively after their bids were directly criticised by the IOC.

In Chicago, meanwhile, they probably just had a swift glass of Goose Island beer before bunkering down to come up with a strategy that will allow them during the next 30 days to convince the IOC members that they are not a potential financial liability if they are awarded the 2016 Olympics.
 

The race to host an Olympics is bit like a tactically run 10,000 metres. It meanders for lap-after-lap with only the real aficionados watching it and then the bell goes and suddenly everyone gets interested.
 

But does it matter? A bit like the Evaluation Commission's visit to the four bidding cities in April and May, the Report generates plenty of headlines and column inches but it is harder to measure how much difference it makes in the final ranking. The IOC members are under no obligation to read the 98-page document before they cast their vote in Copenhagen on October 2.
 

I decided to get my scrapbook out and leaf through what I said after the IOC released its Evaluation Report in June 2005, a month before the vote for the 2012 Olympics. This is what I wrote in The Guardian about the glowing report that the Evaluation Commission had given Paris: "If it had been a school report it was the kind you would have run all the way home to show your mum and dad."
 

Overlooked were the limitations of the Stade de France, with its awful sightlines when in athletics mode and poor back-of-house facilities, and the fact that at $480 a night, a room in a five-star hotel in Paris during the Games would be $190 more expensive than in London.
 

I remember Sebastian Coe (pictured) addressing the media a few minutes after he had seen the report and he proclaimed that it was a "springboard" for London to win. "A good evaluation on its own is not enough to get you over the line," he said. "But we have the confidence to build the momentum this bid has enjoyed over the last year. We are in good shape to take the battle even harder and further towards our goal."
 

It was stirring Churchillian stuff that largely fell on deaf ears. The media had already decided that it was a done deal and the Games were heading back to Paris for the first time since 1924. The bookies, who generally don't get much wrong, reacted to the publication of the Report by cutting Paris' odds to win to 1-5.

But London embarked upon a hectic period of shuttle diplomacy which saw them swing crucial votes behind their cause and momentum quickly built that ultimately carried them over the line in Singapore. The city that will win the race to host the 2016 Games is the one that wins the last month of campaigning. 

That momentum is currently definitely behind Rio. Steve Wilson, the hugely respected and experienced Olympic writer on Associated Press, reflected this yesterday when he wrote "the Rio bandwagon seems to be picking up speed", a story that appeared under the headline the "IOC keeps on loving city's bid".
 

But as Mike Lee, who is advising Rio on strategy, well knows from his time as the Director of Communications & Public Affairs for London 2012, this is not the time for any city to be resting on its laurels. All of the four candidates currently have teams travelling the world trying to speak to IOC members and convince them of the merits of their particular city. Nothing can be taken for granted and nor will it be.
 

I finished my article on the Commission's Report four years ago in The Guardian with the prescient comment:  "For all that the hierarchy of the International Olympic Committee want the Games to go to Paris, the members can be a volatile constituency".
 

The bubbly is already on ice in Copenhagen. It is just that no-one knows yet which city will be popping the corks.

Duncan Mackay is the publisher and editor of insidethegames.biz. He was the 2004 British Sports Journalist of the Year and was the athletics correspondent of The Guardian for 11 years, being the only British daily newspaper writer to correctly predict in 2005 that London's Olympic bid would be successful.