From The Mixed-Up Files of Mrs. Basil E. Frankweiler (1995 Film) - Authenticity

Authenticity

The film lacks the narrative of Mrs. Frankweiler present in the book which causes it to lose much of the book's humor and wisdom . For the majority of the film, the script stays true to the action in the book. However, Claudia's posing as an adult and Jamie's cold are not present in the novel. TV Guide asserts that these changes may differ from the book, but bring added drama to the film.