Most horror movies involving haunted homes seem to have that one fundamental flaw in common: when things start getting creepy and people get hurt, why stay in the house?

If you’re willing to overlook the characters’ lack of common sense in this regard, “Paranormal Activity 3? may very well be the scariest entry of the franchise.

This time, we see supposedly found footage from 1988, featuring “Paranormal Activity” sisters Katie and Kristi (the sisters Grimm?) as children. We get to meet their mother — and, in a clever plot device, her boyfriend, Dennis, a wedding videographer who decides to set up video camera in the house to catch the action when things start going bump in the night…and in the day.  Turns out the curious happenings are a product of Kristi’s relationship with her imaginary friend, Toby, who may actually be a demon.

There are three elements that combine to make “Paranormal Activity 3? effective: excellent use of silence; clever set up of a camera affixed to an oscillating fan; and the believability of Chloe Csengery and Jessica Tyler Brown, the young actresses who play Katie and Kristi, respectively.  Hiring “Catfish” directors Henry Joost and Ariel Schulman didn’t hurt either. These two have an instinct for suspense, and though the product of that instinct is clichéd, it still works.

Perhaps the most curious aspect of “Paranormal Activity 3? is the disconnect between the film’s trailer and the actual movie. Most of what you see in the trailer is not in the film, including the expert who appears to diagnose Kristi’s issue. Instead, Joost and Schulman show great restraint by leaving that character on the cutting room floor and letting the audience draw its own conclusions.

Three-and-a-half out of five stars.

Copyright 2011 ABC News Radio.