NAEP Report Card: Science

NAEP science results are reported as overall average scores on a 0 to 300 scale at grade 8. In addition to an overall average scale score, results are also reported as average scores, on a 0 to 300 scale, for each content area (Physical Science, Life Science, and Earth and Space Sciences). Science results are also reported as percentages of students performing at or above three achievement levels: NAEP Basic, NAEP Proficient, and NAEP Advanced. Because NAEP scores and achievement levels are developed independently for each subject and grade, results cannot be compared across subjects or grade levels. Read more about the NAEP scaling process in the Technical Documentation.

As required by the NAEP legislation, results are reported for students overall and for selected groups, such as by race/ethnicity, socioeconomic status (SES), sex, disability, and English proficiency. Eligibility for the National School Lunch Program (NSLP) has been used as a proxy for students’ SES and performance trends have been reported since 2003, when the quality of the data on students' eligibility for the program improved. However, as a result of the passage of the Healthy, Hunger-Free Kids Act of 2010, schools were allowed a universal meal service option, the "Community Eligibility Provision" (CEP). Through CEP, eligible schools provide free meal service to all students, regardless of economic status and without the need to collect eligibility data through household applications. CEP became available nationwide in the 2014–2015 school year. Changes in the operation of NSLP led the NAEP program to revise its approach to data collection for NSLP eligibility in order to account for the changes due to the introduction of CEP. Beginning with the 2024 assessment, the variable previously reported as “NSLP eligibility” was relabeled as “economically-disadvantaged" status to better reflect what jurisdictions report and to align NAEP’s terminology with other federal programs that require collecting students’ income status for accountability purposes. The data from the previously used NSLP eligibility categorization have been included with the economically disadvantaged status data to provide trend results for SES.

NAEP SES Index

To better understand SES and its relationship to academic performance, the NAEP program embarked on a series of research and development steps to produce an SES measure that accounts for more than state-reported proxies of SES (as with economically disadvantaged status or NSLP). An expert panel convened for this purpose recommended creating a composite measure of SES using several variables as opposed to using a single variable. NCES-sponsored research found that using student eligibility for NSLP, the overall percentage of students eligible for NSLP at the school the student attends, the number of books in the student’s home, and the highest education level of either parent explained more variance in performance than using any one of these variables as the sole measure. Beginning with the 2024 assessment, NAEP started reporting results for two SES indices described below.

NAEP SES index (3 components)

Available for grades 4, 8, and 12

Component 1: Economically disadvantaged status from school records with the following response categories:

Component 2: Percentage of students in school classified as economically disadvantaged, based on NAEP grade sample with the following summarized response category levels:

Component 3: About how many books are there in your home? (student-reported) with the following response categories:

Total index value: The total index value is the sum of the index points for the components listed above, and it ranges from 0 to 9 for this 3-component SES index. A categorical version of the SES index was created by grouping the index value range into three levels: low SES, middle SES, and high SES.

NAEP SES index (4 components)

Available for grades 8 and 12

Component 1: Economically disadvantaged status from school records with the following response categories:

Component 2: Percentage of students in school classified as economically disadvantaged, based on NAEP grade sample with the following summarized response category levels:

Component 3: About how many books are there in your home? (student-reported) with the following response categories:

Component 4: Parental education: Highest level achieved by either parent (based on student responses to two background questions) with the following response categories:

Total index value: The total index value is the sum of the index points for the components listed above, and it ranges from 0 to 12 for this 4-component SES index. A categorical version of the SES index was created by grouping the index value range into three levels: low SES, middle SES, and high SES.

Results for the SES indices and component variables are available in the NAEP Data Explorer (NDE).

Read more about how student groups are defined and how to interpret NAEP results from the science assessment.

Interpreting NAEP Results

NAEP reports results using widely accepted statistical standards; findings are reported based on a statistical significance level set at .05, with appropriate adjustments for multiple comparisons. Only those differences that are found to be statistically significant are referred to as "higher" or "lower."

Comparisons over time of scores and percentages or between groups are based on statistical tests that consider both the size of the difference and the standard errors of the two statistics being compared. Standard errors are margins of error, and estimates based on smaller groups are likely to have larger margins of error. For example, a 2-point change in the average score for the nation may be statistically significant, while a 2-point score change for a state is not, due to the size of the standard errors for the score estimate. The size of the standard errors may also be influenced by other factors, such as the degree to which the assessed students are representative of the entire population. Standard errors for the estimates presented in this report are available in the NDE.

Average scores and percentages of students are presented as whole numbers in the report; however, the statistical comparison tests are based on unrounded numbers. In some cases, the scores or the percentages have the same whole number values, but they are statistically different from each other. For example, the percentage of fourth-grade Asian/Pacific Islander students was 5 percent in 2019, which was statistically different from 5 percent in 2009. The "Customize data tables" link at the bottom of the page provides data tables from the NDE. The tables offer detailed information on more precise values for the scores and percentages and explain how the two comparison estimates differ from each other.

A scale score that is significantly higher or lower in comparison to an earlier assessment year is reliable evidence that student performance has changed. NAEP is not, however, designed to identify the causes of change in student performance. Although comparisons are made in students' performance based on demographic characteristics and educational experiences, the comparisons cannot be used to establish a cause-and-effect relationship between the characteristic or experience and achievement. There are many factors that may influence average student achievement, including local educational policies and practices, the quality of teachers, and available resources. Such factors may change over time and vary among student groups; therefore, results must be interpreted with caution.