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What does IALS measure?

The IALS study defined literacy as "using printed and written information to function in society, to achieve one's goals, and to develop one's knowledge and potential" (NCES IALS Technical Report).  IALS measured three domains of literacy:

  1. Prose Literacy: the knowledge and skills needed to understand and use information from texts including editorials, news stories, poems, and fiction.
  2. Document Literacy: the knowledge and skills required to locate and use information contained in various formats, including job applications, payroll forms, transportation schedules, maps, tables, and graphics.
  3. Quantitative Literacy: the knowledge and skills required to apply arithmetic operations, either alone or sequentially, to numbers embedded in printed materials, such as balancing a checkbook, calculating a tip, completing an order form, or determining the amount of interest on a loan from an advertisement.

The three domains each encompass a common set of skills relevant for diverse tasks. Scores were reported for each domain.

IALS and the U.S. National Adult Literacy Survey (NALS)

IALS adopted its methodology and scales from the 1992 U.S. National Adult Literacy Survey (NALS). The definition of literacy used in IALS was developed and refined from that used in the 1992 NALS. IALS also adopted a number of items from NALS in order to make the assessments comparable. On the prose and document scales, 50 items from NALS were used in IALS. On the quantitative scale, 26 items were carried over, for a total of 76 NALS items in IALS.  For more information on NALS, visit the collection of NALS publications on the NAAL website.