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NAEP Technical DocumentationSchool Response Rates for the 2008 Long-Term Trend (LTT) Assessment

The following table shows school response rates for the long-term trend (LTT) assessment by school type (public, Catholic, non-Catholic private) and age group. These results do not reflect the inclusion of substitute schools that were later recruited to take the place of nonresponding, originally sampled schools. The table includes rounded unweighted counts and weighted percentages using the school base weight multiplied by the estimated age-eligible enrollment. Because the response rate for private schools was below the NCES statistical standards threshold of 85 percent (the base weighted response rate), a nonresponse bias analysis report (359KB PDF) was prepared.

School response counts and rates for public and private schools before substitution, long-term trend (LTT) assessment, by age and school type: 2008

School type	Eligibility status	Age 9		Age 13		Age 17
		Sample count	Weighted percentage (by base weight and enrollment)	Sample count	Weighted percentage (by base weight and enrollment)	Sample count	Weighted percentage (by base weight and enrollment)
# Rounds to zero. NOTE: Sample counts of schools are rounded to nearest ten. Percentages are rounded. Detail may not sum to totals due to rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2008 Long-Term Trend Assessment.
National Public	Total eligible	300	100.00	310	100.00	360	100.00
	Respondents	290	98.28	300	96.84	340	92.50
	Nonrespondents	#	1.72	10	3.16	30	7.50
All Private	Total eligible	170	100.00	140	100.00	150	100.00
	Respondents	130	72.01	110	79.36	80	60.94
	Nonrespondents	50	27.99	40	20.64	60	39.06
Catholic	Total eligible	80	100.00	60	100.00	60	100.00
	Respondents	70	88.28	60	94.16	40	76.41
	Nonrespondents	10	11.72	#	5.84	10	25.59
Other non-Catholic private	Total eligible	100	100.00	80	100.00	90	100.00
	Respondents	60	54.99	50	64.97	40	43.17
	Nonrespondents	40	45.01	30	35.03	50	56.83

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