“…Another difficulty, of course, is that new theory, better research designs, and more sophisticated methods will come with the future, and this means that we cannot presently evision what the "total data" potentials of a given site might be, much less arrive at the estimated cost of recovery (Moratto and Kelly 1977). And, although it may be possible to calculate data recovery costs based on current methods, etc., it is never possible actually to recover all the data potentially available, partly because the destruction of some kinds of information is an unavoidable result of collecting other kinds.…”