Factual error: A few days prior to Warrens' visit to the Hodgson's family, Janet watches the British comedy TV series "The Goodies" on TV. The episode that she was watching actually aired on December 22 of the year in the UK. Later, when Ed records the interview with Janet, it turns out that it's December the 21st.
Continuity mistake: In the middle of the movie during a non ghost activity kitchen shot the Pyrex bowl on the top shelf moves slightly from one shot to the next. You can see the full frontal pattern in majority of the movie, however, it moves slightly, revealing where there is no pattern visible on the bowl.