English sentence optotypes for measuring reading acuity and speed--the English version of the Radner Reading Charts.

PURPOSE: To develop 28 short sentence optotypes for the English version of the Radner Reading Charts that are as comparable as possible in number and length of words, as well as in difficulty and syntactical construction.
METHODS: Thirty-four English sentences were constructed following the method used for other Radner Reading Charts to obtain "sentence optotypes" with comparable structure and the same lexical and grammatical difficulty. Best comparable sentences were statistically selected and standardized in 50 volunteers. Reading speed and the number of errors were determined. Validity was analyzed with a 124-word long 4th-grade paragraph of the Florida Comprehensive Assessment Test®. Computerized measurements of reading parameters were performed with the RADNER Reading Device (RAD-RD©; in conjunction with a PC and microphone).
RESULTS: The mean reading speed obtained with the 28 selected short sentences was 201.53 ± 35.88 words per minute (wpm), as compared to 215.01 ± 30.37 wpm for the long paragraph. The mean reading times were 4.30 ± 0.79 s and 35.26 ± 4.85 s, respectively. The mean number of reading errors was 0.11 ± 0.34. The correlation between the short sentences and the long paragraph was high (r = 0.76; p < 0.05; n = 50). Reliability analyses yielded an overall Cronbach's alpha coefficient of 0.9743.
CONCLUSION: The present study indicates that the 28 selected English sentence optotypes are comparable in terms of both lexical difficulty as well as in reading length, and it demonstrates the validity and reliability of such sentences as test items for determining reading parameters such as reading acuity and speed.