Who decides when films are based on true events?

Yesterday, out of boredom, I watched an episode of the series Heimsuchucht: Incredible witness reports on Netflix. Before the episode started, there was "The following is a true story." Now, in retrospect, I would like to know who decides that. When I go to this series, it can't be true, I mean it's about ghosts and media. Who decides that it is true?

Such assertions you can confidently locate in the fairyland. Just like X-factor. The serve only for the pleasant scare of the spectator.

The German formula "based on a true giveaway" leaves more backdoors open than the English "The following is a true story."

I think the same as you boldly declare that simply as a "true story".

If something is based on a true givenness, there's much more scope for adorning the truth. Maybe the characters in the series really did exist. Maybe even at certain times they were in certain places or talked about certain topics or did certain things. Only a spark of truth is enough to say that the series is based on a true story. A building that was built on a straw. If the spark is given, you can let your imagination run wild.

Most of the time you do not try to be too unrealistic. Often it is a story that is written around statements by witnesses or partially existing evidence. The gaps are then embellished and so that it then in the cinema someone looks, is added some dramaturgy.

How could the Englishman, who has made the spell in your example, speak out? He could say that there were really people who saw ghosts. So you looked at the scenes from the perspective of the people. That does not mean that the spirits are real. The spirits could be imaginary even in the context of history.

As always it depends.

if someone says "behind my barn are landed alien", then you can either

check if there are aliens there - if so: true story / true story
or report: we have someone here who says that… And then pull the person in front of the camera and let it repeat and then this is also a true story, because they had someone who willingly repeated this story. Whether actually landed behind the barn extraterrestrial, is not examined.