TY - CONF T1 - Modeling variability in item parameters in CAT T2 - Paper presented at the Annual Meeting of the National Council on Measurement in Education Y1 - 2001 A1 - Glas, C. A. W. A1 - van der Linden, W. J. JF - Paper presented at the Annual Meeting of the National Council on Measurement in Education CY - Seattle WA ER -