Building psychometrically equal test forms out of a full test is always a pain in the neck. You need to deal with the hassle of identifying the items with similar characteristics, dividing them into two or more sub-forms and comparing these subforms in terms of their capability to reflect the measurement precision of the full test. Moreover, you need to do a number of calculations as a bonus. I would like to introduce Test Form Building Assistant (TFBA) v1.1, the second free irt tool from irtportal.com . TFBA is an excel spreadsheet specifically designed to assist you in the painful process of test form building. It allows you to successfully create two parallel test forms (up to 45 items each) out of a test (of up to 90 items) without losing much from the measurement precision.
Alper Sahin, Ph.D.
Some Key Features :
1. Automatic Color Coding for similar items (click on the images for a larger view)
2. Test Response Function (TRF), Test Information Function (TIF) and Standard Error (SE) comparisons between Sub-forms
3. TRF, TIF and SE comparisons between the Sub-forms and the full test.