The National Assessment of Educational Progress (NAEP) presents assessment results of student performance in two ways:
NAEP reports results using widely accepted statistical standards; findings are reported based on a statistical significance level set at 0.05, with appropriate adjustments for multiple comparisons. Only differences found to be statistically significant are referred to as higher or lower.
Comparisons over time of scores and percentages or among 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 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.
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. Many factors may influence student achievement including educational policies and practices, available resources, and the demographic characteristics of the student body. Such factors may change over time and vary among student groups.Learn More