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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 4, 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 91 9,530 95 178,800
       Public 100 100 8,940 95 172,500
       Private 73 68 370 96 3,000
Alabama  100 100 130 95 2,900
Alaska 96 89 170 93 2,800
Arizona  100 100 140 95 3,200
Arkansas 100 100 140 94 3,000
California 100 100 310 96 8,000
Colorado 100 100 150 95 2,900
Connecticut  100 100 130 94 2,900
Delaware 100 100 100 95 2,900
Florida  100 100 180 94 5,000
Georgia  100 100 170 95 4,200
Hawaii 100 100 140 94 3,000
Idaho  100 100 160 95 3,200
Illinois 100 100 220 94 4,400
Indiana  100 100 140 96 3,000
Iowa 100 100 180 95 3,000
Kansas 100 100 150 95 3,200
Kentucky 100 100 190 95 3,900
Louisiana  100 100 150 94 3,200
Maine  100 100 200 93 2,900
Maryland 99 99 200 94 3,400
Massachusetts  97 99 210 94 3,900
Michigan 100 100 190 95 3,700
Minnesota 100 99 170 95 3,600
Mississippi  100 100 130 95 3,100
Missouri 100 100 160 95 2,900
Montana 100 98 250 94 2,900
Nebraska 100 100 170 96 3,300
Nevada 100 100 130 94 3,200
New Hampshire 99 99 160 93 2,900
New Jersey 100 100 140 94 2,900
New Mexico 100 100 160 94 2,900
New York 100 100 180 93 4,200
North Carolina 100 100 190 95 4,800
North Dakota 100 100 250 96 2,100
Ohio 100 100 210 94 3,600
Oklahoma 100 100 180 95 3,000
Oregon 100 100 180 94 3,100
Pennsylvania 100 100 190 95 3,900
Rhode Island 100 100 150 94 2,700
South Carolina 100 100 130 95 3,100
South Dakota 100 100 290 96 2,900
Tennessee  100 100 140 95 3,000
Texas  100 100 270 95 6,000
Utah 100 100 150 95 3,500
Vermont  100 100 220 95 2,900
Virginia 100 100 130 95 3,100
Washington 100 100 160 93 3,400
West Virginia  100 100 190 94 3,000
Wisconsin 99 99 240 96 4,100
Wyoming  100 100 170 95 2,200
Other jurisdictions          
     BIE1 88 87 110 91 1,100
     District of Columbia 100 100 120 94 1,800
     DoDEA2 99 98 110 92 2,200
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.