Velocity Norms for Academic Growth

Shuttleworth (1934) suggested that growth standards for stature should be expressed in terms of progress rather than status. Tanner (1952) provided a theoretical framework for the development of clinical standards for growth and advocated velocity standards. Bayley (1956) made the first effort to produce standards for height that took account of tempo. Her paper foreshadowed the landmark paper by Tanner, Whitehouse and Takaishi (1966) on longitudinal standards for height velocity and weight velocity. Incremental growth charts for height and weight have since been produced for use in the United States (Baumgartner, Roche & Himes, 1986; Roche & Himes, 1980).

Have you ever heard of growth velocity norms for academic growth—i.e., the growth rate of reading ability or mathematical understanding? There are three reasons you haven’t, which persisted for most of the 20th century: (a) the absence of sufficient longitudinal data on which to base investigations of academic growth; (b) the analytical methods available to educational researchers who wished to study growth; and, (c) challenges of educational measurement (e.g., dimensionality, lack of scale comparability and common units across instruments). Yet, I submit at the dawn of the 21st century, these obstacles have been overcome.

The most recent two reauthorizations of the Elementary and Secondary Education Act (ESEA) required states to assess reading and mathematics in multiple grades. States have been accumulating data for more than a decade. So, longitudinal data are now feasible for reading and mathematics.

Rogosa, Brandt and Zimowski (1982) advocated the use of longitudinal data collection designs gathering more than two waves of serial measures on the same individuals, accompanied by an analytical methodology focused on the individual growth curve. In their landmark book, Raudenbush and Bryk (2002) included a chapter on formulating models for individual change. Singer and Willett (2003) gave book-length treatment to the modeling of individual change. Perhaps the most enabling resource for the educational research community was Singer’s (1998) article demonstrating how to implement multilevel (including growth) models using one of the most widely available general-purpose statistical packages.

Finally, near the end of the 20th century, a new scale was developed for measuring reading ability. Its significant advantage over previous scales was a new kind of general objectivity, attained by calibrating the scale to an external text-complexity continuum and double-anchoring the scale at two substantively important points, much as temperature scales are anchored at the freezing and boiling points of water (Williamson, 2015).

Combining longitudinal data, multilevel modeling and state-of-the-art measurement scales from The Lexile® Framework for Reading and The Quantile® Framework for Mathematics, Williamson (2016) premiered incremental velocity norms for average reading growth and average mathematics growth. Based on an individual growth model, the incremental velocities reflect the long-term developmental growth of students in a well-established reference population (n > 100,000). Now, it is possible to refer the reading or mathematics growth rates of students observed during schooling to a clearly defined population of growth curves derived from serial measures of students whose reading ability and mathematical understanding were systematically assessed over time.

Baumgartner, F. N., Roche, A. G., & Himes, J. H. (1986). Incremental growth tables: Supplementary to previously published charts. The American Journal of Clinical Nutrition, 43, 711-722.
Bayley, N. (1956). Growth curves of height and weight by age for boys and girls, scaled according to physical maturity. Journal of Pediatrics, 48, 187-194.
Raudenbush, S. W., & Bryk, A. S. (2002). Hierarchical linear models: Applications and data analysis methods (2nd  ed.). Thousand Oaks, CA: Sage Publications.
Roche, A. F., & Himes, J. H. (1980). Incremental growth charts. The American Journal of Clinical Nutrition, 33, 2041-2052.
Rogosa, D. R., Brandt, D., & Zimowski, M. (1982). A growth curve approach to the measurement of change. Psychological Bulletin, 92, 726-748.
Singer, J. D. (1998). Using SAS PROC MIXED to fit multilevel models, hierarchical models, and individual growth models. Journal of Educational and Behavioral Statistics, 24(4), 323-355.
Singer, J. D., & Willett, J. B. (2003). Applied longitudinal data analysis: Modeling change and event occurrence. New York: Oxford University Press.
Shuttleworth, F. K. (1934). Standards of development in terms of increments. Child Development, 5, 89-91.
Tanner, J. M. (1952). The assessment of growth and development in children. Archives of Disease in Childhood, 27, 10-33.

Late Elementary, Middle and High School Educators Needed For Reading Research Survey

Are you an educator who works with struggling readers in late elementary, middle school or high school? Are some of your students reading at levels three years or more below what is typical for students at their grade level? We are interested in your feedback on reading materials often used with students reading at lower levels. We want to hear from you!

Please indicate your interest in being part of our current study (and possibly future studies) by completing the short survey found at

New Advanced Lexile Professional Development Workshop

Take your Lexile Professional Development to the next level! We are excited to announce our newest Lexile workshop, The Lexile Framework in Action: Making Curriculum Content Accessible to ALL Students.

This full-day, advanced workshop will guide curriculum coaches, content specialists, classroom teachers and media specialists in the development of units of targeted text and resources. Our facilitator will lead the group in using resources already in place to support instruction that will target all learners. Current state standards, district curriculum pacing guides and recent student Lexile® measures will provide the foundation for developing customized lesson plans.

We also offer numerous other Lexile workshop options including half- and full-day introductory sessions. Learn more about this new offering and view our full range of workshops at

Interested in training on the Quantile Framework for Mathematics? Visit to learn about our Quantile Professional Development workshops.

Summer Learning Tools From MetaMetrics

Fight summer slide with free tools from MetaMetrics!

Visit Lexile “Find a Book” to submit your Summer Reading Pledge and download our Summer Reading Log. Use the log to track a child’s reading throughout the summer break. Search our database of over 270,000 titles for books within a child’s Lexile range. Enter the child’s Lexile measure, and then narrow the search by selecting topics of interest. You can also use “Find a Book” to check the availability of books at local libraries or purchase titles from major booksellers. When school starts again, share the reading log with the child’s teacher to show his or her dedication to reading.

Keep math skills sharp with the Quantile Summer Math Challenge, a FREE math skills maintenance program based on grade-level standards that help prepare students for college and careers. The program is targeted to students who have just completed grades 1 through 8 and is designed to help kids retain math skills learned during the previous school year. The Summer Math Challenge lasts for six weeks and focuses on one math concept per week. From June 19th through July 28th parents will receive daily emails with fun activities and links to educational resources. When the program ends parents can print an award certificate to celebrate their child’s summer math accomplishment! To learn more, visit

Research Grants Offered to Educational Institutions or Researchers that Evaluate and/or Interpret EFL Reading Comprehension

In partnership with the British Council Assessment Research Group, we invite applications for research which will contribute to our understanding of the construct of EFL reading comprehension and reading comprehension assessment.

The aim of the grants is to build insights into the interaction between features of text and reading tasks that impact comprehension and can inform teaching, learning, assessment and evaluation. These grants will support researchers around the world so they can conduct and disseminate the highest quality research. Two areas of interest have been identified for these grants, reading comprehension and growth in reading comprehension over time.

For more information on the grant proposals and how to apply, visit

Free Lexile Resource: Online Databases

Ever wonder how to access a variety of free text resources that match your child’s or student’s reading ability? In most states across the country access to periodical database services is made available to educators, parents, students and other citizens. Some of these periodical database services provide Lexile measures for millions of newspaper and magazine articles, as well as encyclopedia and reference content. Database providers include EBSCO, Gale, Grolier, ProQuest, and others.

Through these databases, texts are made available to educators, students and parents in each state. For a list of available databases containing Lexile measured texts by state, please see our Guide to Online Periodical Databases Offering Lexile Measures. Talk to your district media services coordinator about accessing these online databases and the Lexile measured texts they contain or visit your state’s database website for more information.

Want to keep up to date on the free Lexile resources available to you? Visit and sign up to receive our email updates.

Vocabulary Matters

Vocabulary matters. From early readers learning sight and high-frequency words to medical students deciphering Latin-based names for the parts of the human body, vocabulary is critical for academic and life success. While students acquire many words indirectly through typical reading experiences and engagement in conversation, research suggests that high-quality direct instruction of vocabulary remains an effective way for students to learn new words. Unfortunately, time limitations and the quantity of potential words preclude educators and parents from providing direct instruction designed to teach all possible vocabulary words.

To address this challenge, MetaMetrics has developed a new technology, Lexile® PowerV, to facilitate the selection of words from a piece of text. Words are selected based on three criteria: challenge level, relevance to the passage, and consequence for later reading experiences. The challenge criteria can be based on either the text complexity (e.g., words that will be hard given this text) or reader ability (e.g., words that will be hard for a particular reader). Words relevant to the passage reflect the key themes of the text based on a corpus analysis of 1.4 billion running words. Lastly, words with high utility (i.e. words that are part of large word families) or have been recognized as important for future academic success are selected where appropriate. For more information about the research underlying PowerV, please see our research briefs Empirical Lexile Measures for Words, Lexile Word Frequency Profiles, and Calculation of Lexile Word Measures Using a Corpus-Based Model and Student Performance Data.

This research initiative has implications for parents, educators, and partners. For parents and educators, MetaMetrics’ Lexile “Find a Book” website provides a portal to PowerV functionality. For select books, PowerV provides targeted vocabulary lists based on either the text complexity of the selection or specific reader ability. The word lists generated by PowerV can be used to inform pre-reading activities and instruction, providing readers with an opportunity to learn critical words before encountering them in text. The utility of these word lists is best illustrated with examples.

Don Quixote by Cervantes has a text complexity of 1410L, and PowerV selected ten words from the book that are important for readers to know, regardless of their individual reading abilities: goatherds, shepherdesses, valorous, earldom, belabored, doleful, covetous, digressions, succor, and chaste. To get a more individualized vocabulary list, a teacher or parent could enter a reader measure for a student. In this example, a reader measure of 1000L was entered and PowerV generated a custom word list that is appropriate for this particular reader: curate, disenchantment, commending, absurdities, lamentations, besought, jousts, renegade, and proverb.

A more contemporary example is Harry Potter and the Sorcerer’s Stone by J. K. Rowling. The first novel in the Harry Potter series has a text complexity of 880L and PowerV identified the words that are important for readers regardless of reading ability: referring, broomstick, defrosting, clouted, unseated, bathrobes, quartets, trances, and alibis. For a fourth grader reading at 600L planning to engage with this stretch text, PowerV identified a custom vocabulary list: chasers, scuffles, piers, bowlers, madam, cloak, boaters, dodges, hushing, and whiskery.

MetaMetrics provides a web service for partners looking to integrate PowerV functionality into their own instructional systems. The service accepts a variety of parameters (text, ISBN, Lexile range, number of requested words) and returns appropriate vocabulary lists. Example usages could include: highlighting of challenge words (if in a digital environment), providing word lists in the front of each book, or pre-reading vocabulary-building activities. For more information about licensing Lexile PowerV, please click here.

Given the importance of vocabulary development for academic success, the word selection provided by PowerV is a critical first step in improving student vocabulary knowledge and reading comprehension. With these words in-hand, parents, educators, and partners all have the opportunity to adopt the instructional approach that best suites the needs of their students. In the end, vocabulary matters.

Lexile by Chapter Guides: Expanded Offerings for a New School Year!

A flurry flutters throughout our nation’s schools as instructors clean classrooms and libraries. Bookshelves are being rearranged. Teachers frantically organize their textbooks and create new bulletin boards. This month, educators gear up with excitement, and refresh their materials (and themselves!) for a new school year. Here at MetaMetrics (developer of Lexile measures), we’re refreshing some of our resources for you too!

Launched last fall, Lexile by Chapter Guides have drawn considerable attention to the utility of Lexile measures in instructional planning. In particular (and as articulated in Tim Shanahan’s blog post this past June), this work helps grades 2-12 teachers think beyond merely using text complexity measures as a way to assign certain texts to students based upon their reading ability. Instead, these Guides help teachers think more about the kinds of instructional scaffolding needed to bridge the gap between the difficulty a particular text presents and the individual student’s unique reading abilities. With a deeper understanding of both the complexity within a book and the reading ability of individual students, educators can more thoroughly explore and prepare for those reader and task considerations in the classroom.

MetaMetrics is pleased to announce that we have added 38 new Lexile by Chapter Guides (LbC) for 33 different titles to our collection. These new Guides are available, along with our previous offerings, on the LbC webpage here. The new titles included represent many books that have been requested by teachers and librarians through our feedback survey; our research into frequently taught full-length works at various grade levels; and also a few that serve to illustrate the importance of this work for instructional planning.

Perhaps most exciting in our new offerings is the inclusion of 16 non-fiction, informational texts. These non-fiction titles (many of which also have discussion guides for teachers collected here) will help provide teachers of science, mathematics, history, social studies, and other content areas access to the same information teachers of literature have enjoyed over the past year.

The planning and preparation that goes on in schools this time of year becomes the foundation for student success over the next many months. We hope Lexile by Chapter Guides are a part of that planning and preparation too. Whether teachers are using these Guides to help them better understand the needs of their instruction, or whether they are sharing them with students to help them anticipate and plan for their own independent reading, Lexile by Chapter Guides are a treasure trove of information that help to spur everyone toward success!

Educators Needed for Early Reading Focus Group

Are you a kindergarten, 1st, 2nd, or 3rd grade teacher, librarian, or reading specialist? Are you interested in hearing about the latest Lexile research in early-reading and sharing your feedback?

Over several years, numerous research studies were conducted to examine the characteristics and features of books intended for early-reading students. This research investigated predictors of text complexity of these books and led to the enhancement of the Lexile® Analyzer (the tool used to determine the Lexile measure of texts).

We are looking for early education professionals to join us in our Durham, NC office and participate in a 90 minute focus group on our outreach efforts related to more precise measurement of K-3 books. Each participant will receive a $50 Barnes & Noble gift card.

Interested? Please complete this short survey. Thank you for your time!

Summer Reading Loss

As we hit heat in the triple digits, summer can seem innervating. Unfortunately, just as kids set into the casual routine of vacation, an insidious truth emerges: some students often return to school with a lower reading aptitude than when they finished school. Among the first to note this phenomenon in 1978, Barbara Hayns determined that different rates of summer learning among students may have a persistent effect over how their educational career develops. In other words, when a student loses skills in summer, it takes her/him a considerable time to catch back up while her/his fellow students continue to improve.

Summer reading loss affects those of lower socioeconomic status, and those of color, disproportionately. In what eminent sociologist Karl Alexander called “turning off the tap,” during the school year schools provide resources that are not available to many people in the summer months. Those with more resources (usually those of higher socioeconomic status or whose parents have more education) tend to do better while the tap is off. Meanwhile, those with fewer resources often feel the strain and suffer disproportionate losses.

However, one solution is to keep reading, either through a formal summer reading program or through a self-directed program. In an effort combat summer reading loss, we’ve created the Summer Reading Pledge on “Find A Book”. Here parents and students can select books that match their Lexile Reading Levels. With the simple Summer Reading Log, parents and students can track a student’s reading progress. It is hard to fathom that the halcyon summer holidays help contribute to an increasing achievement gap among students. Yet, just keeping students engaged with the right books can go along way to narrowing the gap and curtailing summer loss.

MetaMetrics is an educational measurement organization. Our renowned psychometric team develops scientific measures of student achievement that link assessment with targeted instruction to improve learning.