Actor-Inspired Element: From the very beginning, Steven Spielberg wanted Greta (Dr. Eddie's assistant) to sing something by ABBA, but Peter Stormare suggested that she should sing something else, to make the scene more absurd. The Swedish children's song "Små grodorna" ("The Small Frogs") was chosen by Stormare. This song is usually sung on Midsummer Eve parties in Sweden.
Blooper: When Anderton is arresting Howard Marks in the opening, he gives the day's date as April 22nd. The next scene, presumably that same night, says that the nationwide referendum on Precrime is to take place on April 22nd and the following scene has the vote taking place in a week.
Divorced Installment: The movie started out in the hands of Carolco Pictures who intended it to be a direct sequel to Total Recall (1990). Apparently the movie would have been set on a terraformed Mars, where mutants with psychic powers were abducted and used to power the Pre-Crime system. They even intended to bring Arnold Schwarzenegger back to play Quaid as the main character. They apparently even had a script written, but then Carolco went out of business and the rights went to 20th Century Fox. It stayed in Development Hell with them for years until Steven Spielberg and Tom Cruise came on board. Spielberg rewrote the script from scratch, turning it into a standalone movie.
Fake American: Averted. The seemingly American Danny Witwer mentions seeing his father get "shot on the steps of our church in Dublin". This line was added in so that if Colin Farrell's native Irish accent crept into the movie, it would be explainable (although he does give a fairly convincing performance).
The transparent data tiles used by Precrime are being developed in real life. Interestingly, those transparent data tiles are actually Iomega Clik/PocketZip disks with the metal bits (and logos) replaced with the transparent material, making this life imitating art imitating Product Placement.
Also, the multitouch technologies used by gadgets such as the iPhone have some similarity with the Pre-Crime interface. With the iPad this is even closer. Especially to the smaller tablet-sized systems the Precrime officers use.
The Other Darrin: Sean Anderton is played by two different child actors, Tyler Patrick Jones and Dominic Scott Kay.
Jan de Bont was originally going to direct the film, with Spielberg executive producing. After The Haunting (1999) met with a scathing critical reaction and underwhelming box-office returns, however, Spielberg threw de Bont off the project and decided to handle it himself. de Bont is still listed as a producer during the opening credits.
Earlier working scripts implied that the 2054-era movie would be set in a retrofuturistic 1950s-style world, with characters heavily lampshading the psychology of surrounding oneself with artifacts, vehicles, clothing and building designs from that era.