ERIC Number: ED418130
Record Type: Non-Journal
Publication Date: 1997-Jun
Reference Count: N/A
Equating Multiple Tests via an IRT Linking Design: Utilizing a Single Set of Anchor Items with Fixed Common Item Parameters during the Calibration Process.
Li, Yuan H.; Griffith, William D.; Tam, Hak P.
This study explores the relative merits of a potentially useful item response theory (IRT) linking design: using a single set of anchor items with fixed common item parameters (FCIP) during the calibration process. An empirical study was conducted to investigate the appropriateness of this linking design using 6 groups of students taking 6 forms of a pilot test, for an accumulated sample size of 8,357 students. A parameter recovery study was performed to examine the robustness of FCIP under the situation of large standard errors in the item difficulty and guessing parameters. Comparison of these results to those produced by the characteristics curve method (CCM) was pursued. Based on the empirical portion of this study, ability estimates calibrated from this linking design are very consistent, except for students with extreme (especially low) ability under the CCM equating method. Item parameter estimates calibrated from this linking design are also very consistent, except for guessing parameters under the CCM equating method. Based on the results from the simulation portion of the study, this linking result can produce very precise and stable parameter estimates. (Contains 7 tables, 19 figures, and 49 references.) (Author/SLD)
Publication Type: Reports - Evaluative; Speeches/Meeting Papers
Education Level: N/A
Authoring Institution: N/A