NAEP Technical DocumentationResults of NAEP Differential Item Functioning (DIF) Analysis for the Science 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, science combined national and state main assessment, by differential item functioning (DIF) category and grade: 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 Science Assessment.
4	C-	0	1	1
	B-	3	8	1
	A	106	101	106
	B+	2	1	3
	C+	0	0	0
8	C-	3	1	0
	B-	7	1	1
	A	107	112	114
	B+	2	4	4
	C+	0	1	0
12	C-	3	0	0
	B-	8	1	1
	A	111	118	119
	B+	4	7	6
	C+	0	0	0

Number of polytomously scored items, science combined national and state main assessment, by differential item functioning (DIF) category and grade: 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 Science Assessment.
4	CC-	0	0	0
	BB-	0	1	0
	AA	50	50	51
	BB+	1	0	0
	CC+	0	0	0
8	CC-	0	0	0
	BB-	3	1	1
	AA	59	65	66
	BB+	6	2	1
	CC+	0	0	0
12	CC-	1	2	1
	BB-	2	1	4
	AA	67	70	66
	BB+	4	1	2
	CC+	0	0	1

Items identified as 'C' items in at least one comparison, science combined national and state assessment, by block and grade: 2009
Grade	Block	Item	Scale	Comparison	Group favored
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2009 Science Assessment.
4	S7	K085001	Earth and space science	Black-White	White
4	S7	K085001	Earth and space science	Hispanic-White	White
8	S5	K121403	Physical science	Female-Male	Male
	S9	K114901	Physical science	Female-Male	Male
	S10	K156601	Earth and space science	Female-Male	Male
	S9	K114901	Physical science	Black-White	White
	S9	K156001	Physical science	Black-White	Black
12	S6	K142801	Physical science	Female-Male	Male
	S9	K128201	Physical science	Female-Male	Male
	S10	K141501	Life science	Female-Male	Male

Items identified as 'CC' items in at least one comparison, science combined national and state main assessment, by block and grade: 2009
Grade	Block	Item	Scale	Comparison	Group favored
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2009 Science Assessment.
12	S8	K142401	Earth and space science	Female-Male	Male
	S3	K139001	Life science	Black-White	White
	S8	K142401	Earth and space science	Black-White	White
	S3	K139001	Life science	Hispanic-White	White
	S5	K131001	Physical science	Hispanic-White	Hispanic

Last updated 06 January 2016 (GF)

Printer-friendly Version