Reading Materials
The reading materials provided for this study were two separate graded reader series, the
Oxford Bookworms and the Penguin Classics. For this study, only levels 1-6 were provided for
the participants, as no starter levels were available. However, it is estimated, that in total, there
were approximately 500-600 graded reader books available for this study, with a minimum of
50-100 books available for participants to select from at each level.
The graded reader levels are determined by the number of head words used by the
publishers for each series. A headword is similar to a dictionary entry where a group of words
share the same basic meaning (e.g. helps, helping, helpful, helpless). The two graded reader
series were selected due to their similarities in head word ratings