TY - CONF T1 - Maintaining a CAT item pool with operational data T2 - Paper presented at the annual meeting of the National Council on Measurement in Education Y1 - 1997 A1 - Levine, M. L. A1 - Segall, D. O. A1 - Williams, B. A. JF - Paper presented at the annual meeting of the National Council on Measurement in Education CY - Chicago IL ER -