Sometimes it's better to rely on gut instinct than the numbers.

Netflix data is often considered to be the soundproof way the streaming giant knows a show is going to be a hit, but it turns out the data isn’t always correct. Vulture’s in-depth new profile on the streaming company (entitled “The Netflix Binge Factory”) includes interviews with Ted Sarandos, Netflix’s chief content officer, and Cindy Holland, Netflix’s vice president of original content, and the executives admitted the data isn’t always right. One example where the data proved wrong in a big way: “The End of the F***ing World.”

Adapted from the graphic novel of the same name by Charles Forsman, “The End of the F***ing World” made its international debut on Netflix starting January 5. The series’ lower profile source material and the fact it had already aired in full on Channel 4 in the United Kingdom months earlier could have been two reasons why Netflix data warned executives not to get their hopes up about the original series performing above expectations with subscribers. Sarandos confirmed the company’s “internal forecasts” came in well below the numbers at which the show actually performed around the world.

“It was astounding how popular it was for us,” Sarandos said. “On one level, it was a massive failure that we didn’t see [the success coming].”

The smash success of “The End of the F***ing World” taught Sarandos and his Netflix team a valuable lesson that data isn’t everything. As the series’ popularity grew, Sarandos started to ask his team, “What else are you highly confident about that you can’t see coming?” One name the company won’t understermate moving forward is Charlie Covell, the creator and writer of “The End of the F***ing World.” Netflix has given a 10 episode order for the writer’s “Kaos,” based on stories from Greek mythology.

While Netflix data isn’t always right, it does give the company an advantage in being able to see which shows are performing with different audience demographics and using that information to predict the success rates of future projects. Holland explained data is key in giving a forecast of how many viewers will show up for a series once it is made available for streaming.

“We have projection models that help us understand, for a given idea or area, how large we think an audience size might be, given certain attributes about it,” Holland said. “We have a construct for genres that basically gives us areas where we have a bunch of programs and others that are areas of opportunity.”

Sarandos and Holland were adamant in their interviews that data is seen by the company as a tool and not a rule by which it makes all of its decisions. Sarandos made it clear that despite rumors saying Netflix data runs the show behind the scenes, it’s ultimately gut decisions and human opinion that matter more.

“It’s 70 percent gut and 30 percent data,” Sarandos said, “Most of it is informed hunches and intuition. Data either reinforces your worst notion or it just supports what you want to do, either way.”

“The End of the F***ing World” is now streaming on Netflix. Head over to Vulture to read the full Netflix behind-the-scenes profile.

Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.