NAEP administered the TEL assessment beginning in 2014. For the first year of the TEL assessment in 2014, new scales and achievement levels were established. Scales for the three content areas and the three practices for grade 8 were developed separately—all scales range from 0–300 with a mean set at 150. Achievement levels are reported as the percentages of students performing at or above three NAEP achievement levels (NAEP Basic, NAEP Proficient, and NAEP Advanced).

Because the NAEP TEL scales were developed independently for each content area and practice, scale score results cannot be compared across content areas or practices. However, these reporting metrics greatly facilitate performance comparisons within each content area and practice from year to year and from one group of students to another in the same grade.

Results are reported for students overall and for selected demographic groups such as by race/ethnicity, gender, and students’ eligibility for the National School Lunch Program (NSLP). In 2018, new sample procedures were implemented for American Indian/Alaska Native (AI/AN) students. Schools with enrollment greater than 5% AI/AN students were oversampled to increase the number of AI/AN students assessed in TEL in 2018. The number of AI/AN students sampled increased from about 120 students assessed in 2014 to 220 students in 2018. Please interpret with caution when comparing AI/AN results between 2014 and 2018. Note that results are not available for Native Hawaiian/Other Pacific Islander students due to an insufficient sample size.

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 one student demographic group may be statistically significant, while a 2-point score change for another student group is not. The size of the standard errors may also be influenced by other factors such as how representative the assessed students are of the entire population. When an estimate has a large standard error, a numerical difference that seems large may not be statistically significant. Standard errors for the estimates presented in this report are available in the NAEP Data Explorer (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, 50 percent of eighth-grade students who took the 2018 TEL assessment were male, which was statistically different from the 50 percent of test takers who were female. The “Customize data tables” link at the bottom of the page provides data tables from the NDE. The tables offer detailed information 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 of students' performance are made based on demographic characteristics and educational experiences, the results cannot be used to establish a cause-and-effect relationship between student characteristics and achievement. Many factors may influence student achievement, including educational policies and practices, available resources, and the demographic characteristics of the student body. Such factors may vary among student groups.