Touringplans.com has a database of theme park wait times dating back to 2006. Over the years, we have seen those wait times flucuate up and down with the seasons but still remain fairly stable from year to year. Yes, wait times are different between busier times like Thanksgiving week and less busy times like early January but when you compare the same period from one year to the next the times are comparable—until this year. Wait times in 2015 are up, big time.
Determining whether wait times are up or down is not as easy as it might seem. Having a few million wait times stored away is a good start but we can't just look at one year to the next and compare. We have to take into account that a difference between one year and the next might be attributed to something other than a year-over-year trend. For example, if we compare June 1, 2014 to June 1, 2015 we must take into account that the former was a Sunday while the latter was a Monday. Sundays and Mondays can be different in ways that have nothing to do with a year-over-year trend. Adjusting for day of the week is easy but what about other factors. The number of school districts in session might change from year to year for a certain period of time, for example. Throw in other important predictors like attraction closures, proximity to holidays, weather, special events, et cetera and suddenly the adjusting becomes very complicated. Luckily, the statisticians step in and give us some math-magic called partial dependence. With partial dependence plots we can see how a particular factor varies over time when we hold constant everything else we know about. In our example, let's look at the partial dependence plot of date and hold everything else constant. In other words, show me how wait times have changed over time without letting that other stuff get in the way.
With all else equal, wait times in 2015 are increasing at Walt Disney World. Image by TouringPlans.com.
We can see that starting sometime in 2014 wait times start increasing relative to previous years. It also shows some shortlived trends from the past. The trend that began in 2014 is strong and seems intent on continuing for the near future. What is interesting about a graphic like this is that it gives us a fair assessment of whether wait times are increasing or decreasing. It accounts for all the things that we know impact wait times and gives us the trend of what is left behind. Often we hear people say something like “Wait times are up because school holidays started sooner this year,” or “The parks are open later than they were so crowds are larger,” but this chart already adjusts for that. It doesn't do a good job telling how much the wait times are increasing but it does give evidence that they are indeed increasing—something that many guests have noted in 2015.
As for what we do this information, that is another question. Certainly, guests planning to visit in 2016 or later may have to prepare a little differently. It may be that “busy” is the new normal.
