------------------------------------------------------------------ Classification INFIT OUTFIT Explanation Investigation ------------------------------------------------------------------ Hard Item Noisy Noisy Bad item Ambiguous or negative wording? Debatable or misleading options? Muted Muted Only answered by top people At end of test? ------------------------------------------------------------------ Item Noisy Noisy Qualitatively different item Incompatible anchor value Different process or content? Anchor value incorrectly applied? ? Biased (DIF) item Stratify residuals by person group? Muted Curriculum interaction Are there alternative curricula? ------------------------------------------------------------------ Muted ? Redundant item Similar items? One item answers another? Item correlated with other variable? ------------------------------------------------------------------ Rating scale Noisy Noisy Extreme category overuse Muted Muted Middle category overuse Poor category wording? Combine or omit categories? Wrong model for scale? ------------------------------------------------------------------ Person Noisy ? Processing error Clerical error Idiosyncratic person Scanner failure? Form markings misaligned? Qualitatively different person? ------------------------------------------------------------------ High Person ? Noisy Careless Sleeping Rushing Unexpected wrong answers? Unexpected errors at start? Unexpected errors at end? ------------------------------------------------------------------ Low Person ? Noisy Guessing Response set "Special" knowledge Unexpected right answers? Systematic response pattern? Content of unexpected answers? Muted ? Plodding Caution Did not reach end of test? Only answered easy items? ------------------------------------------------------------------ Person/ Judge Rating Noisy Noisy Extreme category overuse Extremism? Defiance? Muted Muted Middle category overuse Conservatism? Resistance? ------------------------------------------------------------------ Judge Rating Muted Muted Apparent unanimity Collusion? ------------------------------------------------------------------INFIT: information-weighted mean-square, sensitive to irregular inlying patterns
See Wright & Stone, Best Test Design, p. 2-4, 66-82, 23-24, 121-125, 165-190, and Wright & Masters, Rating Scale Analysis, p. 19-23, 94- 105, 108-111 for basics, and 132-135, 147-151, 171-178, 190-198 for examples.
Diagnosing Misfit, B Wright Rasch Measurement Transactions, 1991, 5:2 p. 156
Forum | Rasch Measurement Forum to discuss any Rasch-related topic |
Go to Top of Page
Go to index of all Rasch Measurement Transactions
AERA members: Join the Rasch Measurement SIG and receive the printed version of RMT
Some back issues of RMT are available as bound volumes
Subscribe to Journal of Applied Measurement
Go to Institute for Objective Measurement Home Page. The Rasch Measurement SIG (AERA) thanks the Institute for Objective Measurement for inviting the publication of Rasch Measurement Transactions on the Institute's website, www.rasch.org.
Coming Rasch-related Events | |
---|---|
Oct. 4 - Nov. 8, 2024, Fri.-Fri. | On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com |
Jan. 17 - Feb. 21, 2025, Fri.-Fri. | On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com |
May 16 - June 20, 2025, Fri.-Fri. | On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com |
June 20 - July 18, 2025, Fri.-Fri. | On-line workshop: Rasch Measurement - Further Topics (E. Smith, Facets), www.statistics.com |
Oct. 3 - Nov. 7, 2025, Fri.-Fri. | On-line workshop: Rasch Measurement - Core Topics (E. Smith, Winsteps), www.statistics.com |
The URL of this page is www.rasch.org/rmt/rmt52k.htm
Website: www.rasch.org/rmt/contents.htm