The NAAL assessment questions were open-ended and so required scoring by trained scorers. NAAL experts have developed scoring rubrics that detail the rules necessary for scoring each assessment question.
In order to make NAAL scores meaningful, the scores were grouped into performance levels to provide information that could more easily be understood and used by the public and policy makers. The performance levels were developed to characterize the status of English language literacy of American adults and include: nonliterate in English, below basic literacy, basic literacy, intermediate literacy, and proficient literacy. The 2003 NAAL performance levels are different from the five levels NCES used to report NALS results in 1992. However, in order to make comparisons across years, the 1992 data were re-analyzed and the new performance levels were applied to the 1992 data.