TK07: Tong - Kolen (2007)

Description Usage Format Source


This (unidimensional) dataset includes three parameter logistic model (3PL) item parameter estimates from simulated dataset based on items from the 1992 Iowa Test of Basic Skills vocabulary test. The data are for six groups (grades 3-8) with varying numbers of common items between adjacent grades.




A list of length two. The first element pars is a list of length six. Each of the list elements in pars is a n x 3 matrix of item parameters where n differs for each grade. The second list element in TK07 is a list of length five identifying the common items between adjacent groups in pars. Each list element in common is a j x 2 matrix for j common items. For example, there are 13 common items between grades 3 and 4. The first list element in common is for the common items between these grades. The first column in the matrix show that items 14-26 in grade 3 are the same as items 1-13 in grade 4. Similar matrices are identified for all other grade pairs.


The parameters were obtained from Dr. Ye Tong at Pearson Educational Measurement and were used in the following article:

Tong, Y. & Kolen, M. J. (2007) Comparisons of methodologies and results in vertical scaling for educational achievement tests. Applied Measurement in Education, 20(2), 227-253.

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