While NAAL does not measure "illiteracy" per se, adults who cannot read well enough to attempt or to correctly answer the minimum number of basic literacy questions in the 2003 NAAL may be classified as not literate in English.
A number of steps were taken to preserve comparability between the 1992 NALS and 2003 NAAL. First, almost half of the 2003 sample questions are taken from the 1992 assessment. Second, the new 2003 test questions are similar to those used in 1992. Third, NAAL uses the same sampling and data collection procedures as NALS to ensure that NAAL participants are similar to those surveyed in 1992. Fourth, 2003 results are along the same literacy scales as those used in 1992—prose, document, and quantitative. Finally, the 1992 NALS data have been reanalyzed along new, 2003 NAAL performance levels.
NCES does not plan to establish grade-level equivalents because they are unsuitable for characterizing the skills of adults (who often have uneven skills across different literacy areas).
NAAL questions reflect the tasks and stimulus materials that adults encounter in daily life. A school-based assessment like the National Assessment of Educational Progress (NAEP) focuses more directly on a participant's ability to read, and less on a participant's ability to apply what they have read to accomplish everyday literacy goals. Also, NAAL is 100 percent open-ended (requires short-answer responses), and questions are placed before the stimulus material so that respondents have to search the text for information. School-based assessments like NAEP have a percentage of multiple-choice questions and answers, and questions are placed after the stimulus material, so that students have to read the entire text for full comprehension before answering the question.
In terms of scoring, NAAL differs from school-based assessments because it scores responses as partially correct if they lead to partial accomplishment of the task. NAAL offers greater insight into the correlation between participants' skill levels and their ability to function in society than does a school-based assessment.
The most recent international assessment of adult literacy is the Adult Literacy and Lifeskills Survey (ALL), an international comparative study conducted in 2003 to provide six participating countries—Bermuda, Canada, Italy, Norway, Switzerland, and the United States—with information about the prose and document skills, as well as the numeracy skills, of their adult populations.
It is important to note that NAAL and ALL are fundamentally different, with different survey designs and goals. For example, as a national assessment, NAAL uses authentic prose and documents, in their entirety, that adults living in the United States encounter in everyday life, such as telephone bills. On the other hand, as an international assessment, ALL uses prose and documents that have been identified as suitable for use across countries. Thus, the stimulus materials may have been constructed, modified, or simplified for comparability. In this sense, they do not fit NAAL's definition of authentic, everyday literacy tasks. Similar constraints are imposed on the types of assessment tasks that are developed. After months of inventing and evaluating various scenarios to integrate the two assessments, NAAL developers reached the conclusion that the two assessments were too different to obtain benefits from integration. View more information on the major differences between NAAL and ALL.