It would be an understatement to say that the supposed "reality" of Out of Body experiences has not yet been proved to the satisfaction of materialistic science. Yet, it is often said that the Astral travelers themselves have no doubt of the reality of their experience.

Yet, many attempts have been made to "validate" OBEs, often with mixed results, or only to the satisfaction of the Astral projector him/herself.

What follows is a first attempt to compile a list of testimonies which "proved" the objectivity of the OBE at least to their experiencers.

Robert Monroe

The most interesting attempt at getting objective data to validate Robert Monroe's OBEs is narrated by Charles T. Tart in his introduction to Monroe's book Journeys out of the Body.
Tart describes the inconclusive attempts in a laboratory setting to get Monroe to go in his Second Body and read some words written on a piece of paper in the next room. Monroe failed to do so but reported other details that were verified, but Tart couldn't testify that Monroe couldn't have known those details by other, more conventional means.

Another time, Tart tried to set up a visit by Monroe out of body to his home where Monroe had never been. The random time Tart chose to concentrate with his wife on Monroe corresponds to the time when Monroe, far away in his own home, started to feel a tugging which he understood as the signal to visit Tart. However, Monroe's subsequent description of Tart's home was way off the mark.

Tart concludes:

What do I make of this? This is one of those frustrating events that parapsychologists encounter when working with poorly controlled phenomena. It is not evidential enough to say that it was unquestionably a paranormal effect, yet it is difficult simply to say that nothing happened. It is comfortable to stick with our common-sense assumptions that the physical world is what it seems to be, and that a man (or his sense organs) is either located at a certain place and able to observe it or he is not. Some OOBEs reported in the literature seem to fit this view, while others have a disturbing mixture of correct perceptions of the physical situation with "perceptions" of things that weren't there or didn't happen (to us ordinary observers). Mr. Monroe reports a number of such mixed experiences in this book, especially his seeming to "communicate" with people while he is having an OOBE, but their never remembering it.

In fact, Monroe spends a fair amount of his first book, Journeys out of the Body, to describe his own attempts at validating his experiences. He was originality scared to death, scared of dying, or worse, as he says, scared of loosing his sanity. Thus during his first years of Astral projecting, Monroe was particularly eager to objectify his experiences. In the book, he notes several experiences:

In 1958, Monroe wants to Astrally project to his friend, Dr Bradshaw, who was ill and supposed to be in bed. Monroe wanted to see if he could describe Dr Bradshaw's bedroom, in which he had never been. Instead, Monroe was surprised to see the good doctor and his wife outside. In the evening, Monroe spoke to the Bradshaws on the phone who, without knowing of his astral visit, confirmed that they were indeed outside of their home at the specified time. Monroe concludes:

The great point is that I had expected to find him in bed, and didn't. The coincidences involved were too much. It was not important to prove this to anyone else. Only to me. It proves to me-truly for the first time-that there might well be more to this than normal science and psychology and psychiatry allow-more than an aberration, trauma, or hallucination- and 1 needed some form of proof more than anyone else, I am sure. It is a simple incident, but unforgettable. In this visit to Dr. Bradshaw and his wife, the time of visit coincides with the physical event. The autosuggestion hallucination factor is negative. I expected to find Dr. Bradshaw in bed in the house, but did not do so and was puzzled by the inconsistency. Identical reports with conditions of actual events:
(1) Location of Dr. Bradshaw and his wife.
(2) Position of the two relative to each other.
(3) The actions of the two.
(4) Wearing apparel of the two.
Possibility of unconscious preknowledge through earlier observation of the above:
(1) Negative, had no information of their change in plans or time habits of post office visits.
(2) Indeterminate, consciously at least unaware of who walks first.
(3) Negative, would have no preknowledge of their walking across to the garage in such fashion.
(4) Indeterminate, may have observed both in similar dress, but expected to find only one (Dr. Bradshaw), in bedclothes.

See more examples in chapter 3 of the book.