These statistics show that the situation is getting worse, at least in the US. This is significantly more than in 2003, when about 30 million adults in the United States were below a basic literacy level ( National Center for Education Statistics 2003). Statistics in the United States suggest that one in six adults has weak literacy skills, which is equivalent to about 52.4 million adults ( OECD 2013).
2016), and other studies have shown that low literacy skills also correlate with adverse health conditions ( Boyes et al. Results from the Program for the International Assessment of Adult Competencies (PIAAC) indicated that for all participating countries, workers with low levels of literacy proficiency had incomes among the lowest 20% in their country ( Grotlüschen et al. Implications for vocabulary measurement are suggested.Īdult literacy is an important issue around the globe. Finally, both breadth and depth contribute independently to explaining variance in reading comprehension. Second, the results of the factor analysis indicated two distinct vocabulary factors. First, we confirmed that all of the assessments were highly reliable for adults with low literacy skills. They completed 12 tasks that have been used in past studies to measure vocabulary breadth, depth, and reading comprehension. Furthermore, to explore the predictive validity of the different aspects of vocabulary knowledge, we assessed the relationship between vocabulary breadth, vocabulary depth, and reading comprehension in adults with low literacy skills. We believe that not only is vocabulary multidimensional, but depth of vocabulary knowledge should also be assessed with multiple measures since it too, is composed of multiple aspects. The purpose of this study was to examine the factor structure of vocabulary.