With an excursion to the movies now costing upwards of $20 these days (once you factor in popcorn and a beverage), movie ratings sites have exploded in popularity in recent years. From Rotten Tomatoes to IMDB, moviegoers often tend to check what both critics and everyday folks think of certain films before plunking down their hard-earned cash for a night out at the movies.

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That being said, you might want to take those movie ratings you see online with a grain of salt. Walt Hickey over at Fivethirtyeight recently took a look at a number of online movie ratings sites and found that you might want to steer clear of reviews on Fandango.

Several sites have built popular rating systems: Rotten Tomatoes,1 Metacritic2 and IMDb3 each have their own way of aggregating film reviews. And while the sites have different criteria for picking and combining reviews, they have all built systems with similar values: They use the full continuum of their ratings scale,4 try to maintain consistency,5 and attempt to limit deliberate interference in their ratings.6

These rating systems aren’t perfect, but they’re sound enough to be useful.

All that cannot be said of Fandango, a NBCUniversal subsidiary that uses a five-star rating system in which almost no movie gets fewer than three stars, according to a FiveThirtyEight analysis.

What’s more, the site found that the methodology Fandango uses to aggregate scores results in artificially inflated movie ratings. This is troubling because Fandango’s entire business rests on selling movie tickets, often at a premium. The conflict of interest here is obvious, with Fandango clearly standing to benefit from high movie ratings across the board.

In looking at hundreds of Fandango movie ratings, FiveThirtyEight found that 75% of films had a 4-star rating or higher while nearly 100% of all films had a 3-star rating or higher.

“It seemed nearly impossible for a movie to fail by Fandango’s standards,” the site adds.

The chart below is rather telling.

movie rating data

While one might understandably attribute Fandango’s inflated ratings to the fact that the site may attract movie lovers who are more prone to enjoying a wider range of films, a deep dive into some of Fandango’s HTML backend reveals that the site tends to round up its ratings scores, sometimes by as much as half a star. For instance, FiveThirtyEight found that the true rating of Ted 2 on Fandango was 4.1. But instead of rounding it down to four stars, Fandango rounded it up to 4.5 stars.

Asked to comment, Fandango said that their rounding up practice was the result of a software bug and that they plan to fix it as soon as they can.

Make sure to hit the source link below for even more data and details surrounding which movie ratings sites are trustworthy and which ones are not. It might end up saving you some cash, or at the very least, a few hours of your life.