Vocabulary.com was built from the ground up to align with the recommended best practices for effective vocabulary instruction. Why? We wanted to build something that works.

Just as there's a clear body of evidence on the importance of vocabulary acquisition, there's also an abundance of scholarship on how to teach vocabulary effectively. What follows is a summary of key findings from that research, along with how we've applied those ideas to the way Vocabulary.com teaches words.

Where We Looked

National Reading Panel
The National Reading Panel (NRP) was established by Congress in 1997 to evaluate existing research to find the most effective ways of teaching children to read. The panel considered 100,000 studies published since 1966, and selected several hundred studies for its final review and analysis. The NRP published a comprehensive synthesis of its findings and recommended a number of best practices for vocabulary instruction.

What Works Clearinghouse
What Works Clearinghouse (WWC) is a federal resource that evaluates evidence-based techniques for teaching. Based on its review of the research, WWC published a number recommended practices for teaching academic content literacy to English Language Learners.

How Vocabulary.com Aligns with Best Practices

Key finding: Curriculum integration is crucial.
"Provide direct instruction of words within a specific text."
Source: National Reading Panel

We make it easy to seamlessly integrate Vocabulary.com with your curriculum. Whether you choose to create your own lists based on the source texts you're using in class, or you select one of the thousands of ready-made lists that have been created by our curriculum team, we'll focus your students' learning on the unfamiliar language they'll encounter in the texts they're reading for class.

This approach aligns with research conducted by Anderson and Nagy (1991), which found that "there are precise words children may need to know in order to comprehend particular lessons or subject matter." Based on this study, the NRP recommends that teachers provide explicit instruction of the words that students will encounter in the texts they're expected to read.

Key finding: Focus, and go for depth.
"Choose a small set of academic vocabulary for in-depth instruction."
Source: What Works Clearinghouse

On Vocabulary.com, students focus on a small active set of words in their personal Learning Program. At any given time, each learner is working toward mastering the words in their Learning Program, until they're ready for new words. Learning a word means more than memorizing a single definition. Vocabulary.com teaches words by systematically exposing students to a wide array of question types, real-world examples, and activities.

WWC explains that, "When students are taught a large number of words in a day, they often develop only a shallow understanding of a word's meaning that is rarely retained later." They recommend that instruction be focused on a small set of academic and content-area words so that students "learn concepts and nuances associated with a given word, and… have time to practice."

Key finding: Ask questions, engage learners.
"The most effective techniques involve questioning and language engagement."
Source: National Reading Panel

The core of Vocabulary.com's approach to teaching words is questioning. We have ten different question types, including antonym, synonym, fill-in, and image questions. Each question type is designed to get students to engage with language in a different way, and to think flexibly about words and how they work in different contexts. Our approach requires students to apply their knowledge and think critically about how language works.

Researchers found that, "When children 'know' a word, they not only know the word's definition and its logical relationship with other words, they also know how the word functions in different contexts." (Stahl and Kapinus, 2001) Recommended best practices state that the best way to accomplish this level of understanding is to incorporate questioning and language engagement into instruction.

Key finding: Offer repeated encounters, different contexts.
"Provide multiple exposures in a variety of contexts."
Source: National Reading Panel

Vocabulary.com makes sure that students encounter the words they're learning multiple times, at varied intervals. Each of a word's key meanings is represented by multiple questions that require students to closely read and actively engage with the text. And because we have so many questions to pull from (211,000 and counting), students don't memorize answers, they develop a real understanding of each word.

Several major studies concluded that in order to learn and retain new words, students need to see them in a variety of contexts on multiple occasions. Researchers cautioned educators to avoid "mere repetition or drill." (Stahl, 2005) Drawing from this finding, the NRP recommends that students be exposed to words multiple times in a variety of contexts.

Key finding: Focus on Tier II / academic vocabulary.
"Teach words that are useful in many contexts."
Source: National Reading Panel

Vocabulary.com requires students to focus on high-frequency, multiple-meaning words that are so crucial to understanding academic texts. Students learn the whole word and have to prove mastery on each meaning. By learning the kinds of words that they're most likely to encounter in literature, nonfiction texts, and standardized tests, they're better prepared to tackle the challenging language they'll encounter in the classroom and beyond.

Research by Beck, McKeown, & Kucan (2002) concludes that "the direct instruction of high-frequency words "known and used by mature language users can add productively to an individual's language ability." Based on this finding, the NRP recommends that students receive frequent, direct instruction in Tier II academic vocabulary that they will encounter across all subject areas.

Key finding: Repetition is essential.
"Teach words... intensively across several days."
Source: What Works Clearinghouse

On Vocabulary.com, students focus their learning on the words they need to learn most. They're exposed to multiple questions at varied intervals on every definition of every word they're learning until they can prove that they know it inside and out. And once they've mastered a word, we follow up occasionally with brush-up questions so they won't forget. By providing multiple exposures and intensive practice, students get the repetition and reinforcement they need to retain new vocabulary.

WWC's paper states that many ELLs are not getting enough opportunities to develop the "sophisticated, abstract, academic vocabulary" that's needed to support the reading, writing, and discussion of the various content areas they're studying in the classroom. The report refers to several studies on this area of need, and recommends that students have a chance to intensively study a small set of words related to academic content over several days.


A Review of the Current Research on Vocabulary Instruction, National Reading Technical Assistance Center and the National Reading Panel. Compiled, written, and edited by Shari Butler, Kelsi Urrutia, Anneta Buenger, Nina Gonzalez, Marla Hunt, and Corinne Eisenhart. Developed by the National Reading Technical Assistance Center, RMC Research Corporation. (2010) https://www2.ed.gov/programs/readingfirst/support/rmcfinal1.pdf

Teaching Academic Content and Literacy to English Learners in Elementary and Middle School, What Works Clearinghouse: Baker, S., Lesaux, N., Jayanthi, M., Dimino, J., Proctor, C. P., Morris, J., Gersten, R., Haymond, K., Kieffer, M. J., Linan-Thompson, S., & Newman-Gonchar, R. (2014). Teaching academic content and literacy to English learners in elementary and middle school (NCEE 2014-4012). Washington, DC: National Center for Education Evaluation and Regional Assistance (NCEE), Institute of Education Sciences, U.S. Department of Education. Retrieved from the NCEE website: http://ies.ed.gov/ncee/wwc/publications_reviews.aspx.