This report reviews earlier work relating Lexical Knowledge (children's understanding of words), working memory span, phonological awareness and the development of word reading. It is suggested that some models of the development of word reading have not been able to account for the interaction between critical factors but may also either conceal or inflate the salience of certain factors. Data from a pilot study (Gibbs, 1997) is presented which within a statistical model using LISREL) indicates how lexical knowledge and phonological awareness covary over the course of development (between the ages of 5- and 7- years) but do not necessarily make independent contributions to variance in word reading. It is also conjectured (and some evidence presented which does not disprove the conjecture) that having a small memory span may, in conjunction with better lexical knowledge, facilitate the growth of phonological awareness. Memory span itself, however, does not in the LISREL analyses that have been carried out appear to make any contribution to word reading ability.
It is hoped that the findings of this report may be tested (to see if they can be disconfirmed) in a further study which replicates and extends the data available from this pilot.
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