A poor report from the International Olympic Committee's evaluation team can probably cost your city the chance to host the Games.
But can an outstanding write-up really win it for you?
The inspectors have completed their tour of the five bidding cities and in June, they will submit their conclusions to the IOC.
When that report is published and a ranking of sorts becomes clear, there will be those who assume that the voting will be a mere formality.
But they would be wrong. History tells us the favourites rarely win.
Athens looked certain to host the Centenary Games in 1996, but lost out to unfancied Atlanta.
The Greek capital of course came good for 2004, when the smart money was on Rome, and everyone thought they would be walking on the Chinese wall in 2000, but of course we all went to Sydney and not Beijing.
A bid is won and lost not exclusively in the written word, but also in the creation of a positive perception, a sense of natural justice and whose turn it is.
In the past, careful lobbying mingled with the odd bit of "incentivisation".
I say in the past because after the lobbying and incentivising got out of hand during the battle for the 2002 Winter Games, infamously won by Salt Lake City, the rules changed radically.
IOC chief Rogge (right) has laid down strict rules since he replaced Juan Antonio Samaranch (left)
Contact between representatives of the bidding cities and IOC members is now strictly controlled - almost to the point of making it impossible for the competing cities to well, frankly, compete.
In the past, bids regularly used 'consultants' to draw up detailed dossiers on each of the 120 or so individual voting members, including a comprehensive list of their preferences, from sexual to whether they took sugar in their coffee.
Bids wanted to know exactly which buttons to press in the lobbying process. If a member liked football, you took them to a game.
If they admired a certain breed of dog, you sent them one (see Salt Lake City).
There's a story that does the rounds from the time of the decision for the 1992 Games, where a guest in the same hotel as the IOC members complained to reception he could not get to his bed.
His room had been filled with gifts from the rival bidders by mistake.
These excesses were halted after Salt Lake, and so now in theory the playing field has been levelled.
Bids are not allowed to set up meetings with IOC members.
But if you happen to be sitting in the lobby bar of the hotel where they are staying, and they wander over uninvited and pay for their own drinks, then you are probably not breaking the rules.
I suspect there has been an unusually high number of chance encounters like this so far.
From my own observations, the successful lobbyist needs plenty of stamina. Loitering in the bar until 3am, then up in the breakfast room sipping orange juice by seven.
Memory for faces
He or she also needs to work those contacts incessantly, not be afraid of the cold call or the brush-off, have a gymnastic social flexibility and a great memory for faces.
They have to work within the rules to engineer opportunities to meet IOC members, and let them bring up the issue of how the bid is going.
There are undoubtedly some members who want to bring back the bid city visits.
They believe you have to get a first-hand feeling for which city is going to do the best job, based on an instinct that transcends the technical documents they are all supposed to read.
It is my bet that frankly, quite a few would have made up their minds long before the two-volume 600-page bid books crashed on to their doorsteps.
Increasingly, members seem to be looking for the 'X-factor'.
Beijing had it, so did Pyongchang in South Korea, which only narrowly missed out on the 2010 Winter Games. Clearly, you cannot measure an X-factor or define it in a bid document.
In the end, the voting members will reach their own conclusions, guided in part by the findings of the evaluation commission.
But they will be informed by a whole raft of different factors, and safe in the knowledge that it is a secret ballot, so no-one will ever take you to task for the decision that you make.