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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 each state and from the District of Columbia and Department of Defense schools. 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 student-weighted national school participation rates for the 2009 reading assessment were 97 percent for grade 4 (100 percent for public schools and 73 percent for private schools), 97 percent for grade 8 (100 percent for public schools and 72 percent for private schools), and 83 percent for grade 12 (86 percent for public schools and 52 percent for private schools). Weighted student participation rates were 95 percent at grade 4, 93 percent at grade 8, and 81 percent at grade 12. 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. At grade 12, the school participation rate for private schools fell below the standard for reporting.

Because the grade 12 weighted student participation rate in public schools was below 85 percent (80 percent), a student nonresponse bias analysis was conducted. That analysis showed that the responding student sample differed from the original student sample with respect to race, relative age, and student disability status. After adjusting the sampling weights to account for student nonresponse, the remaining bias was small, with the nonresponse adjusted estimates for the three identified variables differing from the unadjusted estimates by plus or minus 0.1 percentage points.

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, all 52 states and jurisdictions, along with all 18 districts participating in the reading assessment at grades 4 and 8 met this participation rate requirement. Because the weighted school participation rate in Illinois was 84.5 percent, a school nonresponse bias analysis was conducted for the grade 12 public school sample in that state. That analysis showed that the potential nonresponse bias was effectively reduced by including substitute schools and adjusting the sampling weights to account for school nonresponse.  The school participation rates for the remaining 10 states all met the required standard with weighted participation rates ranging from 92 to 100 percent. 

Student nonresponse bias analyses were conducted at grade 12 for Connecticut, Florida, Illinois, Iowa, Massachusetts, New Hampshire, New Jersey, South Dakota, and West Virginia, where the student response rate fell below 85 percent. Across these nine states, after nonresponse adjustments, the percentage difference between nonresponse adjusted sample and eligible student sample was 1.3 percent or less. Based on the student characteristics available, there does not appear to be evidence of substantial bias resulting from student nonresponse.

The tables below provide participation rates before substitution.

Learn more about the sampling design.

National and State
District
School and student participation rates in NAEP reading at grade 8, by state/jurisdiction: 2009
  School participation Student participation
State/jurisdiction Student-
weighted
percent
School-
weighted
percent
Number of
schools
participating
Student-
weighted
percent
Number of
students
assessed
     Nation 97 87 7,030 93 160,900
       Public 100 100 6,510 92 155,400
       Private 72 68 360 95 3,100
Alabama  100 100 110 93 2,700
Alaska 98 88 100 91 2,500
Arizona  100 100 130 92 2,800
Arkansas 100 100 120 93 2,700
California 100 100 230 92 7,200
Colorado 100 100 120 93 2,800
Connecticut  100 100 110 92 2,800
Delaware 100 100 50 92 2,800
Florida  100 100 160 91 4,200
Georgia  100 100 120 93 3,500
Hawaii 100 100 70 92 2,900
Idaho  100 100 110 94 3,000
Illinois 100 100 200 94 4,100
Indiana  100 100 110 93 2,700
Iowa 100 100 130 94 2,600
Kansas 99 99 120 95 2,700
Kentucky 100 100 130 94 3,500
Louisiana  100 100 120 93 2,600
Maine  100 100 140 93 2,700
Maryland 100 100 130 92 3,200
Massachusetts  100 100 140 92 3,600
Michigan 100 100 150 92 3,300
Minnesota 100 100 140 92 2,900
Mississippi  100 100 120 94 2,800
Missouri 100 100 130 94 2,700
Montana 100 98 170 91 2,600
Nebraska 100 100 120 95 2,600
Nevada 100 100 90 92 2,900
New Hampshire 96 96 90 90 2,500
New Jersey 100 100 110 93 2,700
New Mexico 100 100 100 90 2,500
New York 97 98 150 90 3,700
North Carolina 100 100 150 92 4,500
North Dakota 100 100 180 95 2,100
Ohio 100 100 190 93 3,400
Oklahoma 100 100 150 93 2,700
Oregon 100 100 130 92 2,900
Pennsylvania 100 100 150 92 3,500
Rhode Island 100 100 60 92 2,700
South Carolina 100 100 110 93 2,700
South Dakota 100 100 220 95 2,800
Tennessee  100 100 120 93 2,800
Texas  99 100 170 92 5,700
Utah 100 100 110 91 2,800
Vermont  100 100 120 93 2,900
Virginia 100 100 110 93 2,800
Washington 100 100 130 91 2,800
West Virginia  100 100 120 92 2,900
Wisconsin 99 99 170 93 3,400
Wyoming  100 100 90 91 1,900
Other jurisdictions          
     BIE1 80 83 90 89 800
     District of Columbia 100 100 60 89 1,600
     DoDEA2 99 97 60 93 1,600
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 Reading Assessment.