Ill. Admin. Code tit. 23, pt. 25, subpt. L, app A

Current through Register Vol. 48, No. 44, November 1, 2024
Appendix A - Statistical Test Equating - Licensure Testing System

The Z-score formula set forth below will be used in all cases except where none of the scorable items on a test form has appeared on any previous test form. In such cases, the linear equating formula will be used.

Z-Score Formula

The following formula is used for z-score equating.

1. Define:

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2. Set zx = zy

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3. In order to find the equivalent passing score on the new form, solve for Xi, where Yi = the passing score on the previous form rounded to one decimal place.

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The linear equating formula is as follows.

1. Define:

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2. Compute estimated descriptive statistics for the total group (i.e., candidates from new and previous test form administrations).

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3. In order to find the equivalent passing score on the new form, solve for Xi, where Yi = the passing score on the previous form rounded to one decimal place.

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Ill. Admin. Code tit. 23, pt. 25, subpt. L, app A

Amended at 37 Ill. Reg. 8379, effective June 12, 2013