About Lexile® WordBank

Repeated encounters with words in meaningful contexts provide the best opportunity for successful vocabulary development. As a result, curriculum and assessment developers need up-to-date information about the words students are likely to encounter in their school reading to focus attention on the words students will actually encounter.

Lexile WordBank meets two important needs in vocabulary instruction and assessment:
  1. Identifying where and when students will likely encounter words in their school reading.
  2. Prioritizing a subset of high-value words for a specific purpose.

The Lexile WordBank is a vocabulary resource containing approximately 50,000 unique words from the Landscape of American Schools English Corpus created from the top four best-selling textbook programs, all published after 2011, in science, math, social studies, and reading/English language arts (ELA). WordBank provides content, curriculum, and assessment developers with rich information about the words students will likely encounter in their school reading. Data from WordBank can be integrated into existing development systems, where filtering and sorting features can be used to identify the specific words best suited to a particular purpose.

Word Frequency Interpretation

Because the Lexile WordBank is based on multiple textbook programs in each grade and domain, the total number of occurrences of a word (frequency) can be interpreted as the expected number of times a student would encounter a word in their school materials. However, textbook materials are an important source of word exposure for students they are not the only one. Over future releases, the Lexile WordBank will reference additional materials like trade books, online content, and more. The reported frequency measures will remain interpretable as the expected number of encounters for students from grade 1 to grade 12.

Data Manipulation

As the Lexile WordBank is delivered as a standard CSV file, it is expected that licensees will have a working knowledge of how to access and manipulate the data using basic spreadsheet features like sorting, filtering, and merging (for situations where WordBank data is being added to an existing development system).

Lexile Measures

WordBank includes Lexile word measures for nearly 30k words. These Lexile word measures estimate the challenge a particular word presents to a particular reader during independent reading. Lexile word measures were developed with over 7 million reading-comprehension item responses and patterns of word use in MetaMetrics' 1.4-billion-word corpus of K-12 reading materials.

Lexile word measures range from BR to 1825L and can be interpreted as how many challenges they contribute relative to the text in which they appear. For example, if an 800L reader encounters an 800L word in an 800L text, she would be expected to answer a reading comprehension question based on that word 75% of the time. If the same reader encounters a 1200L word in an 800L text, she would be expected to correctly answer a reading comprehension question 50% of the time. Similarly, if a 500L word were encountered in the same 800L text by the same reader, she would be expected to answer a question on that word 87% of the time.