I'm always suspicious of films that start with "based on a true story". It is either an outright lie or so loosely based that it might as well be fiction.

Anyway an American haunting starts with a rather contrived modern day setting were girl has a bad dream and is woken by her mother. The mother spots some old papers which the girl says she found in the attic. Mum then gets plastered on a bottle of vodka while reading the papers which turn out to be the account of a haunting back in the 18 hundreds.

Basically a well-to-do land owning family wrong an old woman who is rumoured to be a witch then shortly after they see strange wolves and the daughter gets attacked by something. At first they think this is the work of slaves of the disgruntled old woman but the attacks become stranger and the girl starts to see spirits and eventually her father is also attacked.

It is all told by the local school master who tries to understand what is going on. The film is quite well made it is not particularly scary. The twist, which I wont spoil, was different but I found the film lacked direction it appeared to be an idea that had some story bolted to it as padding wrapped round some accounts of hauntings. The modern day bit seemed especially superfluous except as a mechanism to underline the point of the twist in big neon highlighter in case you missed it. All in all it wasn't a particularly bad film just one that didn't really have anything to recommend it. Not really good or bad just nondescript.

"Based on a true story"?. OK, in this case it seems to be reasonably likely.

I'll wait a moment for the shock to dissipate.

The reason I think its relatively likely is that the middle section of the film (about 80%) is notably different from the rest. I.e. its actually good. I think what we have here is an account of a haunting turned into a section of film, with an ending and a contemporary meta-story badly glued to it.

The film starts with a dream sequence that is fairly well done but in plot terms basically tells you that you are in the right screen.

We then move rapidly though a brief modern setting into the story proper. The main section of the film is actually quite well done. The pacing is good, not overly drawn out and the actual "visitations" are fairly menacing, with a suitable level of violence for the subject. The characters actually have a level of depth and the setting seems reasonable.

The film uses dream sequences well, and there's some good use of surprise in places. The characters approach the situation in a reasonable manner with the pleasing inclusion of an educated skeptic.

The ending of the old setting story, however, fells like it was written on a Friday afternoon. It doesn't feel like it fits the characters, it seems an easy explanation. It also feels like it was hastily attached to give the audience "closure", Hollywood's habit of forcing stories to have a conclusion (AI was a particularly bad case).

As Evilmatt says, the ending of the colloquial story is purely there to bludgeon the point into the heads of people who somehow missed it.