Flickchart at its core is about two big things: helping you discover and rank movies to develop a coherent chart of your favorites, and mashing everyone’s individual charts into a globe-straddling list of the greatest movies of all time. All the other stuff — social features, recommendations, and so on — flow from these overarching pair of concepts. If either are broken, it’ll ripple through the site in ways small and large.
You’ve all been ranking movies like mad on Flickchart, some of you for years and some of you hundreds of thousands of times. We’ve kept an eye on the global charts and tweaked things here and there in response to feedback or our own gut sense and analysis of how those rankings were being aggregated. But there comes a time to pause and give deeper thought to how the machine ticks; how is “The Best Movies of All Time” shaping up? Let’s look at what it’s been telling us up to today:
What it’s telling us is that we’re on the heels of perhaps the greatest era of film-making in history. Count ‘em: FOUR movies within the past four years that are among the 10 greatest of all time. What a run! Something must have finally clicked with Hollywood to spur them to leave behind such dross as Rear Window, Casablanca, The Godfather, Ghostbusters, and The Shining.
Or… you could subscribe to the notion (as we do) that although excellent, movies like The Avengers vault up the charts on their newness, and that given time they’ll drop in the rankings to a more reasonable level. This is, after all, a list of the greatest movies of all time, and movies released within the past few years aren’t of a sufficient vintage for us to forecast their longevity.
The most obvious flaw in weighting new movies equally with older ones is selection bias: the folks who are way into superhero movies watch The Avengers in the theater, and the ones who love the movie hit Flickchart to rank it and build a digital monument to its greatness. The folks who don’t love it don’t rush to the site in equal measure, meaning that our global stats are drawn disproportionately from the subset of users who are Avengers fans. This effect will lessen as more ambivalent users rank The Avengers in random matchups, but it’s a gradual process — and we want the chart to be as accurate as possible all along the way.
With all that in mind, we’ve significantly changed the algorithm used to compile the global chart. We already use Bayesian inference to express uncertainty about a movie’s true average ranking based on the number of users who have ranked it (a movie ranked by 10,000 users is more “solidly” accurate than one ranked by only twenty); now, the new algorithm also expresses an analogous uncertainty based on how old the movie is. Has it stood the test of time? Does it find an audience beyond the confines of its own generation? The algorithm now defers those questions to time itself.
The end result is that the “The Best Movies of All Time” on Flickchart will consist of fewer films from the 1990s, 2000s, and 2010s. The change in distribution in the top 250, for instance, looks like this:
NOTE: Your personal Flickchart will not be affected by these changes! We’re only talking about the globally aggregated charts here.
Rest assured that we’ll keep our fingers on the pulse of the global rankings going forward, and we’ll continue to refine the algorithm as needed. Let us know what you think, and have fun Flickcharting!