A continuity error is a difference between different frames of the same scene on a film, occurring as result of editing multiple takes of the scene together. The phrase can also refer to inconsistencies in the plot of a film, although this is usually avoided by the employment of a script editor. Nancy B. Hansen was in charge of script continuity in Part I, and Marion Tumen was the script supervisor for Part II and Part III.
Continuity errors that result from the editing process are among the details that fans of the film series enjoy looking for. In imdb.com, these are listed under the heading "goofs".
Some of the more famous oddities in Back to the Future are:
- The candy jar in the McFly home when Biff is confronting George in 1985.
- The mileage reading on the DeLorean's odometer as Marty drives through the Twin Pines Mall parking lot.
- The flaps on Marty's shirt pockets when he and George are hanging laundry on the clothesline in the backyard of the McFly residence in 1955.
- When Marty and Biff grab each other's shirts, clenching their fists in the Hill Valley High School cafeteria scene in the first film, we first see the camera from behind Biff, facing Marty, Mr. Strickland then intervenes and the camera angle faces Biff, from behind Marty. You will see that Marty's hand is no longer grabbing Biff's shirt.