The Vatican has published rules to evaluate the authenticity of the dozens of apparitions of the Virgin Mary reported each year.
The norms mandate that the local bishop must conduct a “serious investigation” to ascertain, with “at least great probability,” whether the Marian apparition effectively took place.
The rules also require an evaluation of the “personal qualities” of the alleged seer, including his or her “psychological equilibrium,” “rectitude of moral life” and “docility towards Ecclesiastical Authority.” The contents of the “revelation” must be “immune” from theological error, and the apparition must bear “abundant… spiritual fruit,” such as conversions.
The authenticity of the vision should be rejected if, among other factors, the alleged seer shows “psychological disorder” or “evidence of a search for profit.”
Tip: CFI’s Morning Heresy
There isn’t a way to tell how strict they are when they evaluate these claims, though. Consider that the investigators have a bias of belief in the divine and presumably accept the reality of miraculous visions. If they REALLY wanted to know the BEST answer that does not rely on a supernatural cause, they ought to consult some skeptical experts.
However, considering that visions are fleeting, there is likely no evidence left to examine except for eyewitnesses accounts. That is the WORST way to determine authenticity. But I do like the “evidence of a search for profit” bit…