It is still possible to entertain the idea that in such experiments there is no true "projection," but rather a combination of successful ESP trials and unintentional PK activity. The ideal experiment for astral projection would probably necessitate not just ESP tasks and mechanical or biological detectors, but also several human observers who could independently attest to the presence of the subject's "astral body" at the moment at which projection is being attempted.

In the meantime, as suggested by psi researcher Carlos Alvarado, a primary objective would be to pay much more attention to the phenomenology of the OBE, as described by those who actually have these experiences; we may discover that terms like OBE or astral projection cover a wide range of different phenomena, and that no single explanation can account for them all.

Additional Sources of Information:
A Further Psychophysiological Study of Out-of-the-Body Experiences in a Gifted Subject, Robert A.
Monroe