Uses Of Rasch Calibration Parameters

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Following the use of Rasch calibration parameters, start points as well as both reverse and discontinue rules were established according to the results of the national standardization process (Kaufman & Kaufman, 2014). Two parallel forms of the KTEA-3 were created, Forms A and B. Scores on both forms were calibrated using equating strategies, including common-person, equipercentile, combining sets of grade-appropriate items, and special linking studies. For the Reading Comprehension, Listening Comprehension, Written Expression, Oral Expression, and Word Recognition Fluency subtests, vertical scaling using item response theory (IRT) concurrent calibration was conducted individually for each form to determine start and stop points.…show more content…
Standardization Sample
Alternate form reliability was computed by administering two parallel forms of the test (Form A and B), both including the 19 subtests of the final edition. Validity was established by administering one of five alternate measures of cognitive ability and academic performance to participants. Standardization data was collected over approximately one calendar year (August 2012 to July 2013). Two sets of sample data were derived, age norm (n = 2,050) and grade norm (n = 2,600), with data for grade norms collected in the fall and spring to obtain expected skill levels at those times of the year. These groups, however, do not yield a total sample size of 4,650 participants; the age and grade norms were calibrated using data from the students at a specific grade level who were of the expected age for that level. This procedure yielded approximately 1,300 students in the fall (grade-based) normative sample and 1,300 students in the spring normative sample. Likewise, there were 1,025 females and 1,025 males in the age norms sample. The KTEA-3 normative sample was stratified and matched the population in the United States, based on the U.S. Census Bureau’s American Community Survey 2012 one-year period estimates (Ruggles, Alexander, Genadek, Goeken, Schroeder, & Sobek, 2010; although citation is 2010, reported census data are from
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