NAEP Analysis and Scaling - Overall Descriptive Statistics for Items as Defined After Scaling, Age 9 Mathematics Long-Term Trend Assessment: 2012

NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Items as Defined After Scaling, Age 9 Mathematics Long-Term Trend Assessment, By Block: 2012

NAEP Technical DocumentationOverall descriptive statistics for item blocks as defined after scaling, age 9 mathematics long-term trend assessment, by block: 2012
Statistic	Item type	Block M1	Block M2	Block M3	Block M4	Block M5	Block M6
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	23	22	26	21	20
	Multiple choice	16	18	17	17	17	14
	Dichtomously scored constructed response	8	5	5	9	4	6
	Polytomously scored constructed response	0	0	0	0	0	0
Unweighted sample size	†	4,100	4,100	4,000	4,300	4,000	4,000
Weighted average item score	†	0.62	0.68	0.68	0.71	0.67	0.64
Weighted average polyserial	†	0.62	0.66	0.60	0.69	0.66	0.58
Weighted alpha reliability	†	0.86	0.85	0.82	0.88	0.85	0.78
Weighted proportion of students attempting last item¹	†	0.79	0.82	0.87	0.79	0.85	0.88

Last updated 15 January 2014 (JL)