This study was focused on examining the hierarchy of readability levels of text selection in
elementary reading textbooks and the similarity of readability levels of narrative and expository texts
at the same grade level. In narrative and expository text selections, the number of paragraphs,
sentences, words, and syllables was measured. the mean number of sentences per paragraph, that of
words per sentence, that of syllables per sentence and that of syllables per word were calculated
through the number of paragraphs, sentences, words, and syllables. Additionally, all the readability
indexes were compared across grade levels and text genres. In narrative and expository texts, the
number of sentences, words, and syllables increases by grade, and the differences in the three indices
across grade levels were least between first and second grade, between third and fourth grade, and
between fifth and sixth grade. The mean number of words per sentence in narrative texts is 6.2,
5.8, 7.0, 7.7, 7.6, and 8.1 each at grades 1-6, but that in expository texts is 7.4, 8.1, 9.3, 10.8,
12.5, and 12.8 respectively across the six grades. The difference in the mean number of words and
syllables per sentence across grade levels is likely to increase with grade. The readability indices also
increase with grade, but the difference in those indices between narrative and expository texts also
grow greater.