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 4, 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	91	9,330	95	156,500
Public	100	100	8,780	95	151,500
Private	73	68	370	96	2,800
Alabama	100	100	130	95	2,700
Alaska	—	—	—	—	—
Arizona	100	100	140	96	3,100
Arkansas	100	100	140	95	2,800
California	100	100	310	95	7,400
Colorado	100	100	150	95	2,700
Connecticut	100	100	130	94	2,700
Delaware	100	100	100	94	2,800
Florida	100	100	180	94	4,700
Georgia	100	100	170	96	4,000
Hawaii	100	100	140	95	2,800
Idaho	100	100	160	95	3,000
Illinois	100	100	220	95	4,100
Indiana	100	100	140	94	2,700
Iowa	100	100	180	95	2,800
Kansas	—	—	—	—	—
Kentucky	100	100	190	95	3,800
Louisiana	100	100	150	94	2,900
Maine	100	100	200	93	2,600
Maryland	99	99	200	95	3,500
Massachusetts	97	99	210	94	3,700
Michigan	100	100	190	94	3,400
Minnesota	100	99	170	95	3,300
Mississippi	100	100	130	95	2,800
Missouri	100	100	160	96	2,700
Montana	100	98	240	94	2,700
Nebraska	—	—	—	—	—
Nevada	100	100	130	95	3,000
New Hampshire	99	99	160	93	2,700
New Jersey	100	100	140	93	2,800
New Mexico	100	100	160	94	2,800
New York	100	100	180	93	4,000
North Carolina	100	100	190	95	4,500
North Dakota	100	100	240	96	2,000
Ohio	100	100	210	94	3,500
Oklahoma	100	100	180	96	2,800
Oregon	100	100	180	94	2,900
Pennsylvania	100	100	190	94	3,600
Rhode Island	100	100	150	95	2,500
South Carolina	100	100	130	95	2,900
South Dakota	100	100	290	96	2,700
Tennessee	100	100	140	94	2,900
Texas	100	100	270	95	6,300
Utah	100	100	150	94	3,300
Vermont	—	—	—	—	—
Virginia	100	100	130	95	2,900
Washington	100	100	160	94	3,100
West Virginia	100	100	200	94	2,800
Wisconsin	99	99	240	96	3,800
Wyoming	100	100	160	95	2,000
Other jurisdictions
BIE¹	—	—	—	—	—
District of Columbia	—	—	—	—	—
DoDEA²	99	98	110	93	2,100
— Not available. The state/jurisdiction did not participate at the state level. 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.