Many initiatives have emphasized the importance of challenging students in text using readability formulas. Almost all formulas employ mean word frequency yet long-standing issues abound. Researchers question using a singular mean with a skewed variable like frequency. They also question the degree to which frequency pinpoints complex words,…

The two studies reported on in this paper examine the features of words that distinguish students' performances on vocabulary assessments as a means of understanding what contributes to the ease or difficulty of vocabulary knowledge. The two studies differ in the type of assessment, the types of words that were studied, and the grade levels and…