NAEP Analysis and Scaling - Overall Descriptive Statistics for Items as Defined After Scaling, Age 13 Mathematics Long-Term Trend Assessment, By Block: 2012

NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Items as Defined After Scaling, Age 13 Mathematics Long-Term Trend Assessment, By Block: 2012

NAEP Technical DocumentationOverall descriptive statistics for item blocks as defined after scaling, age 13 mathematics long-term trend assessment, by block: 2012
Statistic	Item type	Block M1	Block M2	Block M3	Block M4	Block M5	Block M6
† Not applicable. ¹ The "Weighted proportion of students attempting last item" is equal to 1 - (Percent not responding to last item /100). NOTE: Item statistics in this table are described on the page Blocks of Items. Block M4 is an historical block. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2012 Mathematics Long-Term Trend Assessment.
Number of scaled items	Total	24	22	26	36	23	22
	Multiple choice	19	17	18	28	18	17
	Dichtomously scored constructed response	5	5	8	8	5	5
	Polytomously scored constructed response	0	0	0	0	0	0
Unweighted sample size	†	4,200	4,100	4,000	4,200	4,100	4,100
Weighted average item score	†	0.68	0.74	0.69	0.70	0.64	0.71
Weighted average polyserial	†	0.60	0.62	0.64	0.57	0.61	0.64
Weighted alpha reliability	†	0.83	0.82	0.88	0.88	0.83	0.84
Weighted proportion of students attempting last item¹	†	0.92	0.91	0.81	0.69	0.91	0.95

Last updated 15 January 2014 (JL)