NAEP Technical DocumentationSummary Response Rates for the NAEP 2008 Mathematics Long-Term Trend Assessment

Summary item response rates, by item type and age, mathematics LTT assessment: 2008
Age	Statistic	Multiple-choice items	Dichotomous constructed-response items	Polytomous constructed-response items
† Not applicable. ¹ Missing responses include 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), 2008 Mathematics Long-term Trend Assessment.
9	Number of items	103.00	33.00	†
	Average percent missing¹	4.55	5.67	†
	Minimum	0.58	0.67	†
	Maximum	17.05	15.07	†
	Average percent off-task²	†	0.12	†
	Minimum	†	0.00	†
	Maximum	†	1.62	†
	Average weighted proportion correct	66.48	65.69	†
13	Number of items	120.00	36.00	†
	Average percent missing¹	3.05	3.85	†
	Minimum	0.11	0.23	†
	Maximum	25.71	26.39	†
	Average percent off-task²	†	0.02	†
	Minimum	†	0.00	†
	Maximum	†	0.13	†
	Average weighted proportion correct	68.21	66.72	†
17	Number of items	126.00	30.00	†
	Average percent missing¹	3.25	6.50	†
	Minimum	0.42	0.85	†
	Maximum	19.04	28.37	†
	Average percent off-task²	†	0.24	†
	Minimum	†	0.00	†
	Maximum	†	1.28	†
	Average weighted proportion correct	70.28	60.09	†

Last updated 01 November 2011 (JL)