Age appropriateness

[Anne Mangels <amangels@QUIKNET.COM>]

        In all the book selection policies and guidelines I've seen, "age
appropriateness" is mentioned, but not delineated in clear, objective terms.
How does one determine "age appropriateness?"  Is there any consistency in
the standard, so that there would be basic agreement among a range of
individuals?
        I am asking these questions because I am on a "Reconsideration
Committee," evaluating a resource that has been adopted and challenged.  One
of the components of the complaint against the material is that it is age
inappropriate for the intended audience.  Is there a black-and-white
standard which I can apply to this material, or does it boil down to
professional judgment (or in some peoples' eyes, opinion)?