TEACHERS ABILITY TO ESTIMATE ITEM DIFFICULTY - A TEST OF THE ASSUMPTIONS IN THE ANGOFF STANDARD-SETTING METHOD

The Angoff(1971) standard setting method requires expert panelists to (a) conceptualize candidates who possess the qualifications of interes t (e.g., the minimally qualified) and (b) estimate actual item perform ance for these candidates. Past and current research (Bejar, 1983; She pard, 1994) suggests that estimating item performance is difficult for panelists. if panelists cannot perform this task, the validity of the standard based on these estimates is in question. This study rested t he ability of 26 classroom teachers to estimate item performance for t wo groups of their students on a locally developed district-wide scien ce test. Teachers were more accurate in estimating the performance of the total group than of the ''borderline group,'' but in neither case was their accuracy level high. implications of this finding for the va lidity of item performance estimates by panelists using the Angoff sta ndard setting method are discussed.