Why CinemaScore is so important to the box office...

...according to The Hollywood Reporter, at least:

Every Friday night, foot soldiers for the market research firm CinemaScore descend upon theaters in five or six cities across North America. Bearing small survey cards, they ask moviegoers to assign a letter grade to what they have seen.

Back in Hollywood, studio executives anxiously await the results, which come in about 11 p.m. PT and serve as a fairly reliable indicator of whether a film will fly or fizzle. "CinemaScore is definitely one of the tools we use to evaluate playability," says Chris Aronson, senior vp domestic distribution at 20th Century Fox, whose Rise of the Planet of the Apes is benefiting from an A- CinemaScore.

Surprisingly, given the escalating cost of the theater experience, consumers are fairly forgiving. A majority of films receive a grade in the A- to B- range. C grades are enough to keep most filmmakers awake (though Rango, released in March, did fine after it received a C+), and an F has been given to only five films since Ed Mintz founded the Las Vegas-based firm 29 years ago. In that time, only 52 films have received an A+, including The Help and seven Oscar best picture winners:Gandhi, Driving Miss Daisy, Dances With Wolves, Schindler's List, Forrest Gump, Titanic andThe King's Speech.

And with notable exceptions (Cinderella Man?), an A+ CinemaScore signals a long, prosperous theatrical run. Help felt the glow right away, opening to a better-than-expected $35.9 million. Says Dave Hollis, executive vp distribution at Disney, which is distributing the film, "The movie is now set up for a great run, with more and more people exposed to it because of the power of word-of-mouth."

GRADE A+: Only 52 films have received the top mark from audiences, on average two a year since 1982

• Akeelah and the Bee (2006, Lionsgate)
• Aladdin (1992, Disney Animation)
• Beauty and the Beast (1991, Disney Animation)
• The Blind Side (2009, Warner Bros.)
• The Chronicles of Narnia: The Lion, the Witch and the Wardrobe (2005, Disney)
• Cinderella Man (2005, Universal)
• Dances With Wolves (1990, Orion)
• Dead Poets Society (1989, Disney)
• Diary of a Mad Black Woman (2005, Lionsgate)
• Die Hard (1988, Fox)
• Dreamer (2005, Dreamworks)
• Driving Miss Daisy (1989, Warner Bros.)
• Drumline (2002, Fox)
• A Dry White Season (1989, MGM)
• E.T.: The Extra-Terrestrial (1982, Universal)
• A Few Good Men (1992, Sony)
• Finding Forrester (2000, Sony)
• Forrest Gump (1994, Paramount)
• The Fugitive (1993, Warner Bros.)
• Gandhi (1982, Columbia)
• Harry Potter and the Chamber of Secrets (2002, Warner Bros.)
• The Help (2011, Disney)
• Homeward Bound: The Incredible Journey (1993, Disney)
• The Incredibles (2004, Disney /Pixar)
• Iron Will (1994, Disney)
• The Joy Luck Club (1993, Disney)
• The King's Speech (2010, Weinstein)
• Lean on Me (1989, Warner Bros.)
• Lethal Weapon 2 (1989, Warner Bros.)
• The Lion King (1994, Disney Animation)
• Monsters, Inc. (2001, Disney/Pixar)
• Mr. Holland's Opus (1995, Disney)
• Mulan (1998, Disney Animation)
• Music of the Heart (1999, Miramax)
• The Passion of the Christ (2004, Newmarket)
• The Polar Express (2004, Warner Bros.)
• The Princess Bride (1987, Fox)
• Ray (2004, Universal)
• Remember the Titans (2000, Disney)
• Rocky 3 (1982, United Artists)
• Schindler's List (1993, Universal)
• Soul Food (1997, Fox)
• Soul Surfer (2011, Sony)
• Star Trek IV: The Voyage Home (1986, Paramount)
• Star Wars (1999 rerelease, Fox)
• Tangled (2010, Disney Animation)
• Terminator 2: Judgment Day (1991, TriStar)
• Titanic (1997, Paramount)
• Toy Story 2 (1999, Disney /Pixar)
• Up (2009, Disney/pixar)
• When Harry Met Sally … (1989, Columbia)
• Why Did I Get Married? (2007, Lionsgate)

GRADE F: George Clooney's Solaris is one of only 5 to fail

• The Box (2009, Warner Bros.)
• Bug (2006, Lionsgate)
• Darkness (2002, Dimension)
• Solaris (2002, Fox)
• Wolf Creek (2005, Weinstein)

-Joey's Two Cents: It's not the most important thing in the world, but it does seem to be a useful tool in seeing how audiences are responding to new films...thoughts?