The Blair Witch Project is appealing because of how uncertain it feels. From the shaky, found-footage format to the film's hoax-like promotional run, audiences love this film because they never know what's coming next.

As it turns out, this film excels so deeply in that respect because, for the most part, the creators also had no idea what came next, either.

In an interview with The A.V. Club, directors Daniel Myrick and Eduardo Sánchez explained that, while they had a rough outline for what they wanted The Blair Witch Project to be, they frequently encouraged their actors to improvise.

"Dan and I wrote a script that was about 35 pages long, and it was basically a script without any dialogue for the whole film," said Sánchez. "We had always wanted the dialogue to be improvised. We didn't want to put those kinds of limitations on the actors. The prime directive was to not give anything away that was fiction."

Sánchez and Myrick felt that by leaving room for improvisation, they would be rewarded with a more authentic performance that an audience would believe.

"I felt that by giving the actors the freedom to make up their own lines, it would seem a lot more natural than anything we could script," said Sánchez. "Also, we didn't want them thinking about lines. We didn't want them to memorize dialogue. So all the dialogue was improvised. But all the scenes and all the moments are pretty much scripted. There are a couple of surprises, but pretty much everything is laid out in the script."

While the outline served as a guide for both cast and crew, Sánchez maintained fluidity in the filming process, keeping an unpredictability that the film benefited from.

"We not only had our actors improv dialogue, but we were doing improv as filmmakers," said Sánchez. "We were kind of in a state of flux as the film was evolving, and these actors were interacting in this world we created. We were adjusting as we were going along, too. This method approach demanded that."