NAEP endeavors to include as many sampled students as possible in the assessment, including students with disabilities (SD) and English language learners (ELL), and has established specific inclusion goals: 95 percent of all sampled students and 85 percent of sampled students identified as SD or ELL. Inclusion rates were computed for each state/jurisdiction participating in the 2011 assessment and compared to NAEP inclusion goals. Specifically, Wilson confidence intervals were used in order to avoid having an upper bound greater than 1.
Three inclusion percentages were computed for each state/jurisdiction. An overall inclusion percentage represents included students as a percentage of all students sampled within the state/jurisdiction. In addition, separate percentages were computed to report included students as a percentage of the state/jurisdiction sample that was identified as SD or ELL.
Inclusion percentages are estimates based on a sample, and each estimate has a measure of uncertainty or margin of error. Confidence intervals quantify this uncertainty due to sampling, resulting in interval estimates of the inclusion percentages. Therefore, confidence intervals for inclusion percentages were used to determine upper and lower confidence bounds around the inclusion point estimates.
When determining whether each state/jurisdiction met the NAEP inclusion goals, the confidence intervals were used, rather than just the point estimates. In other words, if the inclusion goal, whether 95 percent or 85 percent, fell within the corresponding confidence interval, the state/jurisdiction was considered as having met the goal. Therefore, states/jurisdictions for which the upper bound of the confidence interval was less than 95 percent did not meet the overall inclusion goal.
In 2011, all states met the goal of including 95 percent of all students selected for the NAEP samples, and all but three states (Kentucky, Michigan, and North Dakota) met the goal of including 85 percent of those students identified as SD or ELL selected for the samples.
Read more about the NAEP inclusion policy, including exclusion rates from current and previous assessments in all subject areas.