NAEP Technical DocumentationBlock and Scale Composition, Grade 8 Science Combined National and State Assessment: 2015

Block composition before scaling, grade 8 science combined national and state assessment, by item type and block: 2015

Block	Total number of items	Number of multiple-choice items	Number of constructed-response items
			2-category	3-category	4-category	5-category
Total	166	115	1	21	18	11
S3	17	12	0	1	2	2
S4	18	13	0	2	1	2
S5	18	13	0	2	2	1
S6	17	11	0	4	1	1
S7	16	10	0	1	2	3
S8	18	13	1	1	2	1
S9	14	8	0	1	5	0
S10	17	14	0	2	1	0
S11	16	12	0	3	1	0
S12	15	9	0	4	1	1
NOTE: For a small number of constructed-response items, adjacent categories were combined. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Science Assessment.

Scale composition for new blocks as defined after scaling, grade 8 science combined national and state assessment, by item type and scale: 2015

Scale	Multiple-choice items		Dichotomously scored constructed-response items		Polytomously scored constructed-response items
	Scaled	Dropped	Scaled	Dropped	Polytomous (uncollapsed)	Dichotomous collapsed	Polytomous collapsed	Dropped
Univariate	26	0	0	0	5	2	0	0
NOTE: "Dropped" denotes items that were deleted from the final scaling. "Collapsed" denotes items that had categories that were combined and recoded for scaling.  SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Science Assessment.

Scale composition for trend blocks as defined after scaling, grade 8 science combined national and state assessment, by item type and scale: 2015

Scale	Multiple-choice items			Dichotomously scored constructed-response items			Polytomously scored constructed-response items
	Concurrent	Split	Dropped	Concurrent	Split	Dropped	Polytomous (uncollapsed)	Dichotomous collapsed	Polytomous collapsed	Split	Dropped
Univariate	83	2	4	1	0	0	31	1	6	5	0
NOTE: “Concurrent” denotes items that were scaled as the same items across assessment years. “Split” denotes items that were scaled as different items across assessment years. "Dropped" denotes items that were deleted from the final scaling. "Collapsed" denotes items that had categories that were combined and recoded for scaling. The number of concurrent polytomously scored constructed-response items is equal to the total number in the first three categories under "Polytomously scored constructed-response items". SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Science Assessment.

Scale composition for new blocks as defined after scaling, grade 8 science combined national and state assessment, by item type and subscale: 2015

Subscale	Multiple-choice items		Dichotomously scored constructed-response items		Polytomously scored constructed-response items
	Scaled	Dropped	Scaled	Dropped	Polytomous (uncollapsed)	Dichotomous collapsed	Polytomous collapsed	Dropped
Total	26	0	0	0	6	1	0	0
Physical science	10	0	0	0	1	0	0	0
Earth and space sciences	9	0	0	0	4	1	0	0
Life science	7	0	0	0	1	0	0	0
NOTE: "Dropped" denotes items that were deleted from the final scaling. "Collapsed" denotes items that had categories that were combined and recoded for scaling.  SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Science Assessment.

Scale composition for trend blocks as defined after scaling, grade 8 science combined national and state assessment, by item type and subscale: 2015

Subscale	Multiple-choice items			Dichotomously scored constructed-response items			Polytomously scored constructed-response items
	Concurrent	Split	Dropped	Concurrent	Split	Dropped	Polytomous (uncollapsed)	Dichotomous collapsed	Polytomous collapsed	Split	Dropped
Total	82	2	5	1	0	0	36	1	3	3	0
Physical science	26	1	4	1	0	0	10	0	0	2	0
Earth and space sciences	34	1	0	0	0	0	13	0	1	1	0
Life science	22	0	1	0	0	0	13	1	2	0	0
NOTE: “Concurrent” denotes items that were scaled as the same items across assessment years. “Split” denotes items that were scaled as different items across assessment years. "Dropped" denotes items that were deleted from the final scaling. "Collapsed" denotes items that had categories that were combined and recoded for scaling. The number of concurrent polytomously scored constructed-response items is equal to the total number in the first three categories under "Polytomously scored constructed-response items". SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Science Assessment.

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