Siti Muazizah (2022). “An analysis of the Readability of texts in an English Textbok entitled “English on Target””. A Thesis. Surakarta. Teacher Training and Education Faculty. Universitas Sebelas Maret. 2022.

This research was aimed to investigate the readability level of reading texts and the factors affecting readability in an English textbook entitled “English on Target” based on Flesch (1949), Dale-Chall (1949), and Coh-Metrix (2004) readability formula. This is a qualitative study that employs content analysis method. The data collection in this study is document analysis. The findings of this study show that only few reading texts in the textbook have suitable readability level for eleventh-grade students. Based on each readability formula, there are four texts (Flesch Reading Ease Formula), one text (Dale-Chall formula), three texts (Coh-Metrix Readability formula) that are qualified to be presented for eleventh-grade students. The result of this study also indicates that Average syllables per words, percentage of hard words, Sentence Syntax Similar Value (SYNSTRUTa), and CELEX Frequency Value (WRDFRQmc) are determined as the factors in affecting readability in this study. Thus, the researcher suggests that the teacher can use other source reading materials in teaching reading.