The use of these two different types of measurement methods, performance tasks and self-assessments, resulted in one of the more intriguing findings from the IALS. The number of adults thought to be “at risk” for various factors such as low employment, dependency upon welfare, poor health care, lack of civic participation and so forth, due to low literacy in each nation, was much higher when the performance scales were used than when the self-assessment scale was used. For instance, in Canada, on the document scale, 18.2 percent of adults were assigned to Level 1, the lowest level of literacy based on their performance task results (OECD, 1995, p. 57). This suggested that some 3.3 million of Canada’s 18.5 million adults aged 16 through 65 were “at risk” because of low literacy.

However, on the self-assessment scale of how well they read in daily life, only around 5 percent of Canadian adults, fewer than 1 million, rated their skills in reading for daily life or at work “poor.” For the 3.3 million adults in Level 1, the lowest level of literacy on the document scale, 21.9 percent thought they had excellent reading skills, 26.5 percent thought they had good reading skills, and 23.9 percent thought they had moderate reading skills. Fewer than a fourth (22 percent) of the adults assigned to the lowest literacy level thought their reading skills were poor and 5.7 percent had no opinion (OECD, 1995, p. 192). Similar discrepant findings were found for other nations between the IALS performance tests and the self-assessed reading abilities for the two other literacy scales and for self-assessments of writing and numeracy skills.

Questions of validity. Attempts to define literacy (Venezky, Wagner, & Ciliberti, 1990) and seventy-five years of literacy test development (Sticht & Armstrong, 1994) reveal that there are many different ways to approach adult literacy assessment. The IALS researchers, by their use of two different approaches to assessing adult literacy abilities, standardized performance tests and self-assessments, confirmed once again that there are different ways to construe the nature of literacy and different ways of constructing a representation of the distribution of literacy in a population.

In the IALS, the performance scales and the self-assessments represent two fundamentally different approaches to assessing adult literacy abilities. In the performance assessments, literacy was construed as a cognitive ability or “latent trait” that makes possible the use of printed materials in various contexts. It is considered that some people have more of this capacity than others, although how much people have or lack may not be consciously apparent to them. Nonetheless, it is assumed that these differences in the amount of capacity can be inferred using people’s performance on various “real world” tasks that incorporate the “latent trait” that is theorized to make possible each person’s performance.

In the self-assessment approach to assessing literacy, literacy was considered as an ability or set of abilities (as in reading, writing, and numeracy in the IALS) that adults are consciously aware of and can perceive well enough to estimate how well their literacy skills permit them to negotiate the literacy demands of different sets of activities at work or in their daily life. This requires that adults are aware both of the demands for literacy in the different contexts that they encounter and how well their literacy abilities permit them to meet these demands on a recurrent basis.