NAEP Technical DocumentationResults of NAEP Differential Item Functioning (DIF) Analyses for the Reading Vocabulary Main Assessment in 2009

For dichotomously scored items, NAEP categorizes each item into one of three categories: "A" (items exhibiting no DIF), "B" (items exhibiting a weak indication of DIF), or "C" (items exhibiting a strong indication of DIF). A plus sign (+) indicates that items are differentially easier for the focal group (female, Black, or Hispanic students) than for the reference group (male or White students) after making an adjustment for the overall level of proficiency in the two groups; a minus sign (-) indicates that items are differentially more difficult for the focal group than for the reference group. For polytomously scored items, NAEP categorizes items into "AA", "BB", or "CC" categories and the plus or minus sign has the same interpretation as it does for dichotomously scored items. After reviewing "C" and "CC" items, subject area specialists decided that no items were biased, so none were deleted from the scales for this reason.

Number of dichotomously scored items by severity of differential item functioning, by grade, reading vocabulary national assessment: 2009
Grade	DIF category	Female-Male	Black-White	Hispanic-White
NOTE: Table includes all items in the assessment (the prescaling decisions). SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2009 Reading Vocabulary Assessment.
4	C-	-	-	-
	B-	3	1	5
	A	37	39	34
	B+	-	-	1
	C+	-	-	-
8	C-	2	-	2
	B-	4	4	8
	A	45	49	44
	B+	4	2	1
	C+	-	-	-
12	C-	4	1	1
	B-	11	7	5
	A	32	38	41
	B+	-	1	-
	C+	-	-	-

Last updated 06 January 2016 (GF)

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