Our website is being used to provide information on our upcoming festival.  The festival is scheduled for Saturday, so this is a time-critical question.  Is there any information on the predictive value of the number of unique visitors compared to the actual turnout at an event like a festival?  For planning purposes, it would be great to have an idea of what percentage of unique visitors actually attend the event.  There are other factors that play into this other than unique visitors to the website.  There have been a couple of newspaper articles written about the festival and a local radio interview, as well as promotion on a couple of other websites.  There's also the fact that kids and other people will attend without ever seeing the website.  

I've searched the internet for this kind of information, but have never been able to find anything, so I'm not expecting to get an answer.  It would be great to be surprised, though.  Even if I don't get an answer to help for this year, it would be nice to have it for the future. I'm willing to report our experience after the festival for others who might have the same question.  However, I have to say that we've had a huge surge of visitors in the past week that could cause problems in getting everyone who shows up to park and ride lots to the festival.