About the Assessment: Participation Rates

The schools and students participating in NAEP assessments are selected to be representative of all schools nationally and of public schools at the state level. Samples of schools and students are drawn from participating states and from the District of Columbia and Department of Defense schools. While results for students assessed in Alaska, the District of Columbia, Kansas, Nebraska, and Vermont contributed to the results for the nation at grades 4 and 8, sample sizes were not large enough to report results for these states/jurisdictions separately. The results from the assessed students are combined to provide accurate estimates of the overall performance of students in the nation and in individual states and other jurisdictions. Results are not collected at the state level for grade 12. Because each school that participated in the assessment, and each student assessed, represents a portion of the population of interest, the results are weighted to account for the disproportionate representation of the selected sample. Read more technical information about weighting adjustments made at the school and student level.

National participation

To ensure unbiased samples, NAEP requires that participation rates for original school samples be 70 percent or higher to report national results separately for public and private schools. In instances where participation rates meet the 70 percent criteria but fall below 85 percent, a nonresponse bias analysis is conducted to determine if the responding school sample is not representative of the population, thereby introducing the potential for nonresponse bias.

Before substituting new schools for originally sampled schools that declined to participate, the weighted national school participation rates for the 2009 science assessment were 97 percent for fourth grade (100 percent for public schools, 73 percent for private schools), 97 percent for eighth grade (100 percent for public schools and 72 percent for private schools), and 83 percent for twelfth grade (86 percent for public schools and 52 percent for private schools). Weighted student participation rates were 95 percent at fourth grade, 93 percent at eighth grade, and 80 percent at twelfth grade. The nonresponse bias analysis for private schools at grades 4 and 8 showed that, while the original responding school sample may not have been fully representative, the potential bias was reduced by including substitute schools and by adjusting the sampling weights to account for school nonresponse.

State and district participation

Standards established by the National Assessment Governing Board require that school participation rates for the original state samples need to be at least 85 percent for results to be reported. In 2009, there were 47 states and jurisdictions, along with 17 districts, participating in the science assessment at grades 4 and 8 that met this participation rate requirement.

The tables below provide participation rates before substitution.

Learn more about the sampling design.

School and student participation rates in NAEP science at grade 8, by state/jurisdiction: 2009
State/jurisdiction	Student- weighted percent	School- weighted percent	Number of schools participating	Student- weighted percent	Number of students assessed
	School participation			Student participation
Nation	97	87	6,920	93	151,100
Public	100	100	6,440	92	146,300
Private	72	68	360	95	3,100
Alabama	100	100	110	93	2,700
Alaska	—	—	—	—	—
Arizona	100	100	130	93	2,900
Arkansas	100	100	120	93	2,600
California	100	100	230	93	7,200
Colorado	100	100	120	92	2,800
Connecticut	100	100	110	91	2,800
Delaware	100	100	50	91	2,800
Florida	100	100	160	91	4,300
Georgia	100	100	120	94	3,500
Hawaii	100	100	70	91	2,800
Idaho	100	100	110	94	2,900
Illinois	100	100	200	94	4,200
Indiana	100	100	110	93	2,700
Iowa	100	100	130	93	2,700
Kansas	—	—	—	—	—
Kentucky	100	100	130	94	3,700
Louisiana	100	100	120	92	2,600
Maine	100	100	130	91	2,600
Maryland	100	100	130	92	3,400
Massachusetts	100	100	140	92	3,700
Michigan	100	100	150	92	3,400
Minnesota	100	100	140	93	3,000
Mississippi	100	100	120	93	2,800
Missouri	100	100	130	93	2,700
Montana	100	98	180	92	2,600
Nebraska	—	—	—	—	—
Nevada	100	100	90	91	2,900
New Hampshire	96	96	90	89	2,500
New Jersey	100	100	110	93	2,800
New Mexico	100	100	100	89	2,500
New York	97	98	150	90	3,800
North Carolina	100	100	150	92	4,400
North Dakota	100	100	180	95	2,200
Ohio	100	100	190	93	3,500
Oklahoma	100	100	150	93	2,700
Oregon	100	100	130	92	2,800
Pennsylvania	100	100	150	92	3,600
Rhode Island	100	100	60	93	2,700
South Carolina	100	100	110	94	2,800
South Dakota	100	100	220	95	2,800
Tennessee	100	100	120	93	3,000
Texas	99	100	170	92	5,900
Utah	100	100	110	92	2,900
Vermont	—	—	—	—	—
Virginia	100	100	110	93	2,800
Washington	100	100	130	92	2,800
West Virginia	100	100	120	93	2,900
Wisconsin	99	99	170	93	3,500
Wyoming	100	100	90	91	1,900
Other jurisdictions
BIE¹	—	—	—	—	—
District of Columbia	—	—	—	—	—
DoDEA²	99	97	60	93	1,600
— Not available. ¹ Bureau of Indian Education. ² Department of Defense Education Activity (overseas and domestic schools). NOTE: The number of schools is rounded to the nearest ten. The number of students is rounded to the nearest hundred. The national totals for schools include Department of Defense Education Activity (overseas and domestic schools) and Bureau of Indian Education schools, which are not included in either the public or private totals. The national totals for students include students in these schools. Columns of percentages have different denominators. Detail may not sum to totals because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2009 Science Assessment.