Several procedures have been used to identify differential item functioning (DIF) in NAEP. DIF analyses are conducted for items that have not previously been studied for DIF. Analyses for each assessment involved three comparisons: male vs. female students, White vs. Black students, and White vs. Hispanic students.
They then decide whether the difficult language or contents are part of what is being measured or extraneous to it. In other words, committees determine whether the differential functioning of a particular item is due to bias or not.
For instance, in 2000, results for the SIBTEST procedure were quite similar to those for the Mantel-Haenszel procedure. All but 1 item identified by the Mantel-Haenszel procedure was also identified by SIBTEST. No C or CC items were uniquely identified by SIBTEST. All C or CC items identified by either the Mantel-Haenszel or SIBTEST procedure were evaluated to determine if the items were biased.