NAEP Technical DocumentationSummary Response Rates for the NAEP 2009 Science Combined National and State Main Assessment

Summary item response rates, science national assessment, by item type and grade: 2009
Grade	Statistic	Multiple-choice items	Dichotomous constructed-response items	Polytomous constructed-response items
† Not applicable. ¹ Missing responses includes the categories "omitted" and "not-reached." ² An "off-task" response (constructed-response items only) is a response that is unrelated to the question and is considered inappropriate. 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	Number of items	98	3	43
	Average percent missing¹	9.01	2.54	9.73
	Minimum	0.48	0.86	0.47
	Maximum	35.15	4.45	31.37
	Average percent off-task²	†	0.50	0.24
	Minimum	†	0.03	0.00
	Maximum	†	0.93	0.90
	Average weighted proportion correct	55.38	48.11	36.01
8	Number of items	108	1	57
	Average percent missing¹	4.45	7.07	8.31
	Minimum	0.21	7.07	0.60
	Maximum	25.16	7.07	32.19
	Average percent off-task²	†	1.58	0.68
	Minimum	†	1.58	0.00
	Maximum	†	1.58	2.30
	Average weighted proportion correct	52.12	55.72	32.85
12	Number of items	126	†	59
	Average percent missing¹	3.05	†	10.51
	Minimum	0.16	†	0.46
	Maximum	9.97	†	35.70
	Average percent off-task²	†	†	1.46
	Minimum	†	†	0.00
	Maximum	†	†	5.78
	Average weighted proportion correct	49.83	†	26.28

Last updated 06 January 2016 (GF)