Readability and book leveling are similar in their goals -- helping teachers and educators figure out which books are best for their readers -- but are different in their design and execution. Readability, simply put, is "the ease of comprehension because of style of writing," while book leveling (or leveling in general) is defined as "selecting books to match the competencies of a reader or writer" (qtd. in Fry 286). Obviously, there is much more to these two systems than these bare-bones definitions alone. Readability is usually associated with a numerical score and is much more objective than book leveling, which tends to be less objective and takes more into account other than the physical words, sentences, and pages of the book (286).

History


William Holmes McGuffey is cited as being the first person to develop and distribute the "first widely used 'leveled' set of readers in 1836" (Fry 286). These books, known as the "McGuffey Readers," didn't use grade-level rating designations but instead leveled with a simple numerical rating system (286). (These replaced the age-old method of teaching the children the alphabet, then a few words, before jumping straight into the Bible to continue reading education.)

Formulaic studies of text readability began in the late 19th century. In 1921, Edward L. Thorndike published Teacher’s Word Book, the first comprehensive list of English words based on frequency of use. Thorndike posited that vocabulary knowledge is a strong measure of a reader’s “development, reading comprehension, and verbal intelligence” (DuBay 43). Teacher’s Word Book became the basis for the first readability formulas for children’s books and the oldest method of grading texts: text leveling. Text leveling analyzes vocabulary, format, content, length, illustrations, repetition of words, and curriculum (DuBay 38-44).

In 1928, Mabel Vogel and Carleton Washburne of Winnetka, Illinois contributed valuable research to readability studies by evaluating sentence composition and prepositional phrases in addition to word difficulty and sentence length (DuBay 46).

The 1950s brought several changes to readability formulas. In 1953, Wilson Taylor introduced the cloze test, which is a passage with words removed and multiple choice fill-in-the-blank options. The cloze test was deemed more accurate and detailed than previous readability methods. Studies on reading speed also appeared and revising texts for lower reading levels came into practice. Most importantly, studies in the 1950s began examining prior knowledge, interest, and motivation which readers bring to a text (DuBay 61-62) and criticism of readability formulas continued to be part of the ongoing discussion throughout the 1960s (DuBay 47).

The 1980s saw computer readability programs and a return to text leveling. In 1981, Edgar Dale and Joseph O’Rourke published The Living Word Vocabulary: A National Vocabulary Inventory, which was a return to Thorndike’s theory. Living Word assigned scores to words and their definitions (DuBay 44, 93). The traditional one-dimensional readability formulas were easy for computers to calculate, and many of the initial computer-based programs were based on “words, sentences, and local texts” detached from “discourse meaning” (Graesser 224). Flesch-Kincaid metrics, for example, were based on word and sentences lengths (Graesser 224).

According to Fry, "[t]he use of leveling in modern schools is due in no small part to the work of the New Zealand department of education" (287). Marie Clay, founder of the Reading Recovery system "which used early intervention of reading tutoring for children who had a high probability of failure," brought this idea over to the United States around 1991 (287).

Examples of Readability Formulas

A synopsis of each with a graph comparing the following formulas with others that are available can be found on the Ideosity blog. Here is the link.

Listed below are just a few of the readability formulas available for use (Fry 290).
  • The New Dale-Chall Readability Formula (More information can be found here.)
  • The Fry Readability Graph (More information can be found here.)
  • Lix and Rix
  • The Flesch Kincaid Reading Ease Formula (More information can be found here.)
  • Leveling (A useful tool to level your own books can be found here.)
  • Lexiles, DRP Units, ATOS Grade Level (Accelerated Reader)
  • Betts Levels (This website discusses Betts' Levels of Reading in more detail.)
  • Cloze Procedure (More information can be found here.)

A couple of the more popular readability formulas, Lexile and ATOS, which is used for Accelerated Reader, will be explained in a bit more detail below.
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Lexile score for Diary of a Wimpy Kid: The Ugly Truth

Lexile

Lexile puts the emphasis on individualizing education and providing for each unique student, focusing its leveling system on the student's reading level instead of the grade. (They explain this on their fact sheet by utilizing a comparable scenario that compares reading level to shoe sizes, specifically that we do not buy shoes for children based on their age but by the size of his/her foot. Similarly, Lexile makes the case that reading level is not based on someone's age or grade level.)

Lexile uses two main components of a text to determine its score: word frequency and sentence length ("What is"). These components are measured by MetaMetrics, a computer program that easily determines the Lexile score for thousands of frequently-searched and -read books ("What is"). These scores range from Grade 1 all the way to Grade 17 and are given a score from 100-1800, giving Lexile one of the widest readability scoring ranges among other available formulas (Fry 289). Lexile scores are shown with the assigned number followed by an "L", e.g. Harry Potter and the Sorcerer's Stone is 880L, and scores are measured in variables of 10 ("What is"). Lexile is helpful beyond primary grades, since scores can go as high as 1800, and can easily be used outside of a traditional classroom setting and by more than just teachers and educators.

Because Lexile is one of the most objective readability formulas around, other factors such as "the relationship between a reader and a book, including its content, the age and interests of the reader, and the design of the actual book" can affect how well scored a
particular book is for a particular reader ("What is"). Unlike the ATOS and Accelerated Reader system (which is explained shortly), "there is no clear correlation between the progression of difficulty in the Lexile system and grade equivalent systems" (Burns 37).

Lexile is similar to the the cloze readability formula and received much criticism when it first appeared in 1988. Lexile theorists believed reading comprehension was a “one-dimensional ability” and that “you either understand a passage or you don’t.” (DuBay 94; Graesser 224). Despite criticism, Lexile has become one of the largest and most successful readability systems (DuBay 94). Lexile is still used today in many schools. The Lexile website promotes its services in the classroom and to teachers/educators that may have interest in applying all Lexile's applications ("Lexile @ School"). Those services are linked on this page. Lexile does not market itself to only teachers. It addresses the functions it provides to libraries as well. This page has links to ideas about how to incorporate Lexile into three different areas that are affected by school libraries. It also links to many resources that Lexile provides that may be of interest to librarians ("Lexile @ the Library").

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Accelerated Reader Description of Shooting Kabul

ATOS and Accelerated Reader (AR)

Another popular readability system, Accelerated Reader (AR), claims “there is consensus among key federally funded organizations charged with evaluating educational products that Accelerated Reader is fully supported by scientifically based research” (Accelerated Reader, emphasis original).

Accelerated Reader uses the ATOS readability formula, which
"takes into account the most important predictors of text complexity—average sentence length, average word length, word difficulty level, and total number of words in a book or passage" ("ATOS"). The score itself is broken down into two numbers: the first being which grade level it is most appropriate for, the second indicating during which month of that school year the book could be read based on the new information learned during the current school year.

ATOS and Accelerated Reader have already scored over 150,000 individual books which give schools using the AR program a wide selection of choices and quizzes for students to take ("ATOS"). After books have been analyzed by ATOS, they are given a score in AR Points, used for grade school AR competitions.

Leveling for English Language Learners (ELLs)

In both determining the current state and tracking the development of a child's reading ability, assessment tools such as Lexile and AR theoretically identify the presence of language skills fundamental to the literacy-building process. Assessment of students still in the process of learning English would not accurately reflect literacy skills they might possess within their native language, and so Spanish-language leveling programs have arisen to meet this particular need.

El Sistema Lexile para Leer was created to provide a reading framework for Spanish-speaking students. Billed by Metametrics as "a thermometer for measuring students' reading abilities in their native language that talented educators, involved parents and motivated students use to improve learning" (Lexile.com, n.p.), Sistema Lexile attempts to assess and improve students' reading abilities in their native language while enable parents and educators to provide fitting materials for leisure reading or to supplement curriculum instruction. In a 2000 article in the journal Popular Measurement, author Ellie Sanford (a member of the Metrametrics team and co-developer of Sistema Lexile) argues:
The skills needed to be a proficient reader in English -- identifying, selecting, and collecting information; analyzing, synthesizing, and
organizing information and discovering related ideas, concepts, or generalizations; and applying, extending, and expanding on
information and concepts -- are the same skills needed to be a proficient reader in any language (p. 25).

El Sistema Lexile connects students, educators, and parents with an individual child's Lexile score and a Lexile map of Spanish-language books and authors for each Lexile level. Sistema's website provides this map in PDF form, provides educators with a Spanish Lexile Analyzer to determine "the readability of Spanish-language classroom texts," and offers users the ability to build a custom reading list of Spanish-language materials.

While this system would have the same inherent complications as the original Lexile, it has the added benefit of encouraging young readers to grow in their native language abilities while building their English skills through curricular avenues. Such an approach potentially ensures that English Language Learners both continue their intellectual development and nurture any natural affinity for reading that might be discouraged were they not provided with books appropriate to their abilities and interests.

Like Lexile, ATOS and Accelerated Reader (and their parent company, Renaissance Learning) offer special products for English Language Learners. Star Reading Spanish provides educators and parents with assessments of students' reading abilities in their native language, claiming that such assessments "can indicate what foundational reading skills a students has to transfer to an English-only classroom" (Renlearn.com, n.p.). Assessment information and reports are provided to parents in Spanish, as are further supplemental materials, such as How to Build Successful Readers Early - Strategies for Parents. Renaissance Learning also offers English in a Flash, a vocabulary-building program for ELLs that covers multiple content areas. Accelerated Reader addresses the needs of English Language Learners so that they may continue their intellectual development in their native language alongside their English acquistion. The AR arm also provides Spanish-language informational materials for parents of ELLs, including A Parent's Guide to Accelerated Reader, and A Parent's Guide to AR BookFinder. Students, educators, and parents can all use the AR BookFinder to locate level and interest-appropriate materials in both English and Spanish, thus allowing adjustment for an English Language Learner's differing abilities between the two languages while still locating materials that appeal to her individual interests.

Learn more about these Spanish-language readability assessments:

El Sistema Lexile Para Leer

Star Reading - Spanish

Emerging Issues with Readability Tests


Supporters of computer-based readability formulas believe they are “more reliable and objective than approaches that involve humans annotating and rating texts by hand” (Graesser 223) because “it takes considerable effort to learn how to do leveling accurately. Advanced readers often fail to recognize how difficult texts can be for others” (DuBay 38). Computer programs try to make the process more objective and quicker in order to promote reliability within the given leveling system.

Opponents, on the other hand, maintain that “some characteristics of texts require humans to provide informed, deep, critical analyses” (Graesser 223). For example, traditional readability formulas do not scale the prior knowledge readers need to understand the historical contexts of Shakespeare’s plays or Mark Twain’s novels (Graesser 223). The texts need not be complex for prior knowledge to be an issue. In a recent study of “Jack and the Beanstalk” in Canadian primary schools, students “who were familiar with the European folk tale read the text fluently and answered the comprehension questions accurately” while students who were “recent immigrants to Canada from countries where the ‘Jack and the Beanstalk’ story was not part of their common experience found the passage more difficult than students born in Canada. They did not have knowledge of the characters and the plot to help them make inferences and predictions while reading” (Dzaldov and Peterson 223).

Traditional readability formulas also do poor jobs of differentiating between similar reading levels; in other words, the line between first and second grade reading levels is not clear. Compounding this, different systems (e.g. Lexile, Accelerated Reader, etc.) assign “vastly different grade levels” to the same text, which opponents view as proof of the formulas’ inaccuracies (Compton et al. 177; DuBay 37).

There is another key factor missing from readability formulas: children’s reading interests and motivation. When children first enter school, they are excited about learning. As they grow older this motivation decreases, with the steepest decline occurring between first and fourth grades. Research has linked this lack of motivation to children’s “growing awareness of their own performance as compared to others” as well as to “instruction that emphasizes competition and does not address children’s interests” (Edmunds and Bauserman 415). In other words, children who perform lower on readability tests tend to have a lower interest in reading.

Book Leveling Statistics


In what Brenda Stein Dzaldov and Shelley Peterson term “leveling mania,” many schools are “creating classroom text collections organized by book levels, rather than creating literature-based classroom libraries that are organized by genre, author, or theme.” The result is students’ “diverse interests, unique experiences, and background knowledge” are forgotten and “the diversity of students’ social, cultural, and experiential backgrounds can be whitewashed when matching readers to books” (222). Dzaldov and Peterson surveyed the books sectioned by readability level in schools and found the following:

“About 33% of the books had more males than females, and approximately 33% had no gender representation (i.e. “ungendered” animals). A further 13% of the texts had more females than males, and 21% of the books had the same number of female and male characters.

“In most texts, Caucasian was the most widely represented racial group. In 57% of the texts, one racial group was represented. In only 13% of the texts were more than one racial group represented. These texts included Caucasian characters and characters of another race.

“Middle class and upper class lifestyles were portrayed in 66% of texts. None of the texts analyzed in this study portrayed lower socioeconomic lifestyles” (227).

These findings show why it may be difficult for socioeconomic and ethnic minority children to relate to available texts.

In a related study conducted by Edmunds and Bauserman, children were far more likely to get excited about books they had personal interests in or could relate to, with 84% discussing books they had chosen themselves (417). Children in the study were also excited about books they gained new knowledge from (Edmunds and Bauserman 418), which did not necessarily correlate to the point systems formulated by readability tests. Studies have found that children who enjoy reading have better literacy skills, the result of having typically read three times more than less-skilled readers (Compton et al. 176; Edmunds and Bauserman 415).

With these motivation factors in mind, it is important to let children choose books they are excited about. Teachers and librarians “may unwittingly dampen students’ motivation to read” by restricting children to readability levels rather than opening children to a variety of themes, genres, and characters (Dzaldov and Peterson 223).

Evaluating Books for Pre-readers


When evaluating books for pre-readers, form is often just as important as content--especially for infants. In addition to having thick, easy-to-turn pages, "board books are specifically made for babies: with their stiff, sturdy cardboard pages, nontoxic materials, and glossy sheen easy for cleaning up, they will survive teething, spills, spit-up, and worse" (Sutton and Parravano 8). They are also "less expensive, more durable, and more portable," making them more convenient for parents as well (Sutton and Parravano 8). Because of these factors, many publishers have rushed to adapt popular picture books into board books, often conflating pages or editing out crucial material (Sutton and Parravano 9). Board book adaptations should be evaluated carefully as independent texts to confirm that "it holds together as a story" and is "aimed at babies and toddlers" (Sutton and Parravano 10).

In terms of content, the American Library Association's Association for Library Service to Children (ALSC) provides some examples of board books that will engage babies and promote literacy skills. These qualities include:
  • Books with high color contrast (black/white or bright color), as infants have not yet developed full color vision;
  • Faces, which "babies are predisposed to find interesting" (ALSC n.p.);
  • Common objects to identify (colors, numbers, daily routines), to engage children with interesting pictures and help them develop new vocabulary words;
  • Books to manipulate (lift the flap, tactile books), to engage infants natural kinesthetic learning sensibilities;
  • Playful language, "to support language development and phonological awareness" (ALSC n.p.);
  • American Sign Language, to encourage pre-linguistic communication or to speak with Deaf friends and relatives;
  • Diversity, to reflect the cultural heritage of all readers.

Picture books for toddlers and preschoolers focus on the expanding world of these slightly older children. Books for toddlers begin to "explore the world beyond the safe borders of home and parent" and incorporate "small adventure[s]" (Sutton and Parravano 32). As "four-year-old's worlds have expanded into a larger society," books for preschoolers contain "a lot more tension" without sacrificing satisfying resolutions (Sutton and Parravano 33). Illustrations that support the text and predictable plot help very young readers navigate these books (Sutton and Parravano 37). Patterned language play can also support these pre-readers by introducing rhyme, repetition, and questions (Horning 91-5).

Selecting Books for Adolescent and Teen "Reluctant Readers"


As mentioned previously, reading motivation is closely connected with reading proficiency, and young people's motivation tends to decrease around adolescence. The challenge of motivating readers becomes more difficult as a reader's age increases, partly due to the widening gap between reading level and age appropriate subject matter in reading materials (Spadorcia 33). It is critical that library collections contain books that meet the struggling reader's reading level without plots that seem childish, boring, or embarrassing to him or her.

Hi/Lo Books

"Hi/Lo" books are an attempt to solve this problem. These books, which stand for "high interest low reading level/vocabulary," combine low level texts with interesting and relevant subject matter for adolescents. Hi/Lo books are often marketed as books for "reluctant" or struggling readers, and include non-fiction and sports titles in addition to fiction. There are several prominent Canadian publishers of hi/lo books, including Orca Book Publishers and James Lorimer and Company Ltd (Gleason, 23). Unfortunately, hi/lo books vary in quality, and some have received criticism for sacrificing interesting plots and eloquent writing to achieve "technical readability" with limited vocabulary and short sentences (Rog and Kropp).

Librarians seeking to evaluate the quality of hi/lo books may want to consider the following criteria: authentic and appealing characters, plots that are simple but interesting, "careful introduction and reinforcement of difficult vocabulary and concepts," and illustrations that aid comprehension (Rog and Kropp). Visual details can also make a difference with Hi/Lo books; details like illustrations should be used strategically to break up the text on the page or support comprehension, and book covers should entice struggling readers without advertising its low reading level (Rog and Kropp). Other recommendations for evaluation are to look at the sentences the author uses to begin and end the book, the complexity of pronouns used, and the "types of words" in the book (Spadorcia 54). Ultimately, the ideal books in this genre appeal to average and struggling readers alike.

Series Books

Teachers and librarians unfortunately have a legacy as professionals of disregarding children’s reading interests, and discouraging “low level” or “poor quality” books (Ross 203). Series fiction has been a causality of this history. Series fiction, however, has merits for helping young readers develop literacy skills. When readers are already familiar with a story, they can rely less on the words in front of them and concentrate more on enjoying the story. Series fiction – with familiar plots, characters, and endings – is reassuring to novice readers who are not yet confident in their abilities to select “good” or enjoyable books (Ross 218-223). In addition, one study suggests that the repetitive plots in series fictions are especially important for transitional readers who were never read aloud to (Ross 218). There is no evidence that readers get “stuck” reading series fiction; series fiction is instead a transitional phase through which developmental readers pass on the way to higher level texts (Ross 223).

Graphic Novels

Though often thought of as working against reading and literacy in younger readers, graphic novels in all of their variations -- comics, manga, traditional novel adaptations, etc. -- can be extremely beneficial for reluctant readers. From the very outset, graphic novels carry this cool factor with them that traditional books simply don't have (Fletcher-Spear and Jenson-Benjamin 50). Their interesting and intense union of pictures and words, along with their unique story lines, can appeal to reluctant readers in both their adolescence and teens. The number of differing graphic novels spanning age ranges from very young to not so young, means that there will be reading levels for all readers struggling with traditional books.

Graphic novels also have the ability to "[bring] the subject down to earth" for reluctant readers (qtd. in Fletcher-Spear and Jenson-Benjamin 50). Readers are drawn to graphic novels for more than just their union of text and graphics; they tend to be much shorter than a traditional novel and "[provide] an opportunity to complete a book and have a successful reading experience" (50).

It is often believed "that the textual elements of [graphic novels] may be too unsophisticated for a teen audience; in short, the words are not 'at grade level'" (Fletcher-Spear and Jenson-Benjamin 51). This belief has been disproved by Donald P. Hayes, a sociologist working at Cornell University who conducted a lexicographical survey on a variety of printed media (51). According to his findings, "comics contained an average of 53.5 rare words per one thousand words," where children's books had only 30.9 rare words and adult books only 52.7 rare words (51). Of course, this is only an average and doesn't stand for every single graphic novel. However, to put graphic novels' book leveling into even more perspective, compare it to Stephenie Meyer's blockbuster paranormal teen romance Twilight: it's written at a fourth-grade reading level (51). This information shows that popular literature doesn't always stand up to educators' perspectives or desires; however, that also means that less desirable books could be more useful than originally considered.

Another reason why graphic novels may be successful for reluctant readers is their throwback to children's books and the marriage and images and text. That isn't to say that graphic novels and children's books are the same, but their formulas are very similar. The use of images in graphic novels can help reluctant readers who, "for a variety of reasons, cannot create a mental image of what they are reading" (Fletcher-Spear and Jenson-Benjamin 51). These readers may have trouble conjuring up mental imagery while reading traditional texts and graphic novels provide a "concrete metacoginitive marking point" for readers to physical see what they understand and begin identifying what they do not (51).

Recommended Resources:
YALSA's Quick Picks for Reluctant Readers
Orca Book Publishers

Using Readability Formulas Effectively


Readability formulas can be used as guides to selecting level-appropriate texts for young readers but if our goal is to encourage a lifelong love of learning, it is just as important to keep in mind the reader’s interests (Dzaldov and Peterson 228). It is also important to keep in mind that, as children compare their reading abilities to others, some young readers will want the challenge of a difficult book, some will need to reassurance of an easy book, and others will want a book that is just right. Rather than selecting books for children based on readability charts, perhaps it is best to let them choose books for themselves.

Why Book Levels Can Be Useful


Brenda Weaver wrote a book, Leveling Books, K-6: Matching Readers to Text, that focuses solely upon matching books to the readers through the use of book leveling. Her chapters cover the need for leveling books, understanding the dynamics of book leveling, preparation and steps for leveling books, comparisons of leveling systems, the Weaver reading/writing stages, and where to go next (and includes a glossary of terms). If book levels are used to help readers discover books that will intrigue and challenge their minds, both teachers and librarians serving young people will be better able to advise readers to new materials. (The opposite - readers only looking at levels as assignments - has been addressed fully in a former section on this page.) Libraries are becoming more involved in this practice in more ways than one. The age-old question of which catalog section new books belong in gives way to how best to help students/patrons through reader's advisory with the added impediment (or stipulation) of Accelerated Reader or Lexile points and levels.

Works Cited


Accelerated Reader. http://www.renlearn.com/ar/

ALSC. "Born to Read Book List." http://www.ala.org/alsc/issuesadv/borntoread/masterbooklist

"ATOS Readability Formula." Renaissance Learning. Renaissance Learning, n.d. Web. 24 Nov. 2012.

Burns, Bonnie. "I Don't Have To Count Syllables On My Fingers Anymore: Easier Ways To Find Readability And Level Books." Illinois Reading Council Journal 34.1 (2006): 34-40.

Compton, Donald L.; Appleton, Amanda C.; Hosp, Michelle K. "Exploring The Relationship Between Text-Leveling Systems And Reading Accuracy And Fluency In Second-Grade Students Who Are Average And Poor Decoders." Learning Disabilities Research & Practice (Blackwell Publishing Limited) 19.3 (2004): 176-184. Professional Development Collection. Web. 20 Nov. 2011.

Cregar, Elyse. "Browsing by Numbers and Reading for Points." Knowledge Quest, 39 (4) 2011 p. 40-45.

DuBay, William H. Smart Language: Readers. Readability, and the Grading of Text. Impact Information: Costa Mesa, CA. 2007. Web. National Adult Literacy Database (NALD).

Dzaldov, Brenda Stein and Peterson, Shelley. "Book Leveling And Readers." Reading Teacher 59.3 (2005): 222-229. Professional Development Collection. Web. 20 Nov. 2011.

Edmunds and Bauserman, “What Teachers Can Learn about Reading Motivation through Conversations with Children,” Reading Teacher, February 2006, pp. 414-424 (Available from Academic Search Premier).

Fletcher-Spear, Kristin, and Merideth Jenson-Benjamin. Library Collections for Teens: Manga and Graphic Novels. Bowie, MD: E L Kurdyla, 2011. Print.

Fry, Edward. "Readability Versus Leveling." Reading Teacher 56.3 (2002): 286-291.

Gleason, Carrie. "Mind the Gap." Knowledge Quest 39 (4) Mr/Ap 2011 p. 22-6.

Graesser, et al, “COH-Metrix: Providing Multilevel Analyses of Text Characteristics,” Educational Researcher, 2011, pp. 223-234.

Horning, Kathleen T. From Cover to Cover: Evaluating and Reviewing Children's Books. New York: HarperCollins, 1997.

"Lexile @ the Library" Lexile. MetaMetrics. n.d. 28 Nov. 2012.

"Lexile @ School" Lexile. MetaMetrics. n.d. 28 Nov. 2012.

Rogg, Lori Jamison and Paul Kropp. "Reaching Struggling Readers in the Intermediate Grades with Books they Can and Want to Read." School Libraries in Canada 25 (1), 2005.

Ross, “If They Read Nancy Drew, So What? Series Book Readers Talk Back,” Library and Information Science Research Summer 1995, pp. 201-236 (Available from ScienceDirect)

Sanford, Ellie. "A Spanish Version Of The Lexile Framework For Reading." Popular Measurement 3(1), 2000, pp. 25-26. ERIC. Web. 28 Nov. 2012.

Spadorcia, Stephanie A. "Examining the Text Demands of High-Interest, Low-Level Books." Reading and Writing Quarterly, 21 2005, pp. 33-59.

Sutton, Roger and Martha V. Parravano. A Family of Readers: The Book Lover's Guide to Children's and Young Adult Literature. Somerville, MA: Candlewick, 2010.

"What is a Lexile® Measure?" Lexile. MetaMetrics. n.d. Web. 24 Nov. 2012.

Weaver, B. M. (2000). Leveling books, K-6: Matching readers to text Order Department, International Reading Association, 800 Barksdale Road, P.O. Box 8139, Newark, DE 19714-8139 ($17.95). Retrieved from http://search.proquest.com/docview/62429995?accountid=14553