Sunday, May 30, 2010

Meta-Analysis of Morphological Intervention Studies (Bowers)

Peter Bowers contributed this post. Pete is a doctoral candidate at Queen's University, Canada and the creator of the WordWorks Literacy Centre. Pete authored a prior post on Vocabulogic.

I am pleased to be invited to use this week’s post to describe our meta-analysis on morphological interventions (Bowers, Kirby, & Deacon, 2010) that comes out in the June issue of Review of Educational Research. Vocabulogic emphasizes instruction of morphology among a wide array of vocabulary instruction strategies, so our finding about positive effects of morphological instruction on vocabulary learning is of particular relevance for this blog. Vocabulary, however, was not a special focus of our study. We report on effects for a range of literacy outcomes at the sub-lexical (oral and written features of words), lexical (spelling, reading and vocabulary), and supra-lexical (reading comprehension) levels. Before describing the results, a short refresher on morphology may help.

Morphology: The meaning structure of words
Matrix (Real Spelling dot com)
Morphology is the system by which morphemes combine to construct and represent the meaning of words. For example, the word unhealthy is composed of four morphemes: the prefix un-, the base (also referred to as the root) heal, and the suffixes –th, and –y. Morphemes can also be represented by a word sum (un + heal + th + y unhealthy). Words with a common base are part of the same morphological family and share a connection in meaning. A matrix like the one shown here represents the underlying structure of unhealthy and other members of the same word family. Read more about morphology and morphological awareness here.

English spelling marks the interrelation of morphology and phonology
English spelling uses consistent spellings of morphemes even when pronunciation shifts (see Venezky 1999, 1967 for this and other spelling principles). Note that the base heal needs a grapheme that can represent both the ‘long e’ of heal and the ‘short e’ of health.

Morphology instruction and research
Morphology provides cues of word meanings, influences grapheme-phoneme correspondences, governs spelling changes due to suffixing and marks the grammatical roles of words. With such a fundamental influence on how spelling represents the meaning and pronunciation of words, it is surprising morphology has not played a larger role in teacher training and instruction (Henry, 2003: Nunes & Bryant, 2006; Moats, 2009).

Morphological instruction may have an intuitive appeal for teachers and researchers, but what does the research evidence show? Does morphological instruction actually bring educational benefits? Are the effects similar for less and more able students? How young can morphology be taught effectively? Are there identifiable methods of instruction that are more effective than others?

To investigate these questions, we conducted a meta-analysis of the existing published morphological interventions. (Meta-analysis is a quantitative technique for combining results across different studies.) We found 22 interventions conducted with children in preschool to grade 8 in languages that use the Roman alphabet (18 in English, 2 in Norwegian, 1 in Danish, 1 in Dutch) with a total 2,652 students.

Instructional strategies
A wide variety of oral and written instructional strategies were used. In production tasks such as a cloze or analogy task, children are taught to produce the appropriate word for a given context (e.g., magic/magician; music/________(musician)). Recognition tasks included selecting or sorting words and identifying morphemes within complex words. Problem-solving was an explicit focus in a number of studies (Baumann et al., 2003; Berninger et al., 2003; Bowers & Kirby, 2009; Tomesen & Aarnoutse, 1998). The meta-analysis includes a descriptive table of the morphological content and types of tasks used across the 22 studies.

Findings of our meta-analysis
We found positive effects of morphological instruction but those effects were variable, which is not surprising given the range of participants and instructional methods employed. Analyzing the results for sub-sets of students based on age and ability and comparing types of morphological instruction provides a clearer picture of the effects. We found that morphological instruction was:
  • More effective with less able students
  • Generally more effective in interventions with younger students (Pre-K to Grade 2) than older students (Grade 3 and up)
  • Generally more effective when integrated with other aspects of literacy instruction
Download a conference poster with a table of the results showing effect sizes for morphological instruction compared to control groups and compared to alternative treatments for outcomes at every linguistic layer at this link.

Evidence of greater effects with less able and younger students has important implications for classroom instruction and research. Adams (1990) cautioned against morphological instruction with beginning or less skilled readers. More recently, researchers (e.g., Carlisle & Stone, 2005; Kirk & Gillon, 2009; Lyster, 2002; Tyler, Lewis, Haskill, & Tolbert, 2003) presented evidence challenging that recommendation. Our meta-analysis addresses this debate directly with the finding that young and less able readers gain more from morphological instruction.

“But how do you teach morphology to such young children?” is a common question when I have presented these results at conferences. Perhaps the best response I can provide here is to point to two videos of instruction with young children (Grades 1, 2 and 3) illustrating the kind of morphological content young children can learn and use in the classroom: Video 1 (also available on You Tube) and Video 2 . These young children clearly demonstrate understanding of the internal structures of words and how that system informs the pronunciation and meaning of words.

I hope that this new research evidence and examples of morphological instruction encourages you to consider looking for ways to integrate morphological instruction in your classrooms!


Adams, M. J. (1990). Beginning to read: Thinking and learning about print. Cambridge, MA: MIT Press.

Baumann, J. F., Edwards, E. C., Boland, E. M., Olejnik, S., & Kame'enui, E. J. (2003). Vocabulary tricks: Effects of instruction in morphology and context on fifth-grade students' ability to derive and infer word meanings. American Educational Research Journal, 40, 447-494.

Berninger, V., Nagy, W., Carlisle, J., Thomson, J., Hoffer, D., Abbott, S., Abbott, R., Richards, T., & Aylward, E. (2003). Effective treatment for dyslexics in grades 4 to 6. In B. Foorman (Ed.), Preventing and remediating reading difficulties: Bringing science to scale (pp. 382–417). Timonium, MD: York Press.

Bowers, P. N. & Kirby, J. R. (2009). Effects of morphological instruction on vocabulary acquisition. Reading and Writing: An Interdisciplinary Journal, 23. 515-537.

Bowers, P. N., Kirby, J. R., & S. H. Deacon. (in press). The effects of morphological instruction on literacy skills: A systematic review of the literature. Review of Educational Research, 80.

Carlisle, J. F. & Stone, C. A. (2005). Exploring the role of morphemes in word reading. Reading Research Quarterly, 40, 428-449.

Henry, M.K. (2003). Unlocking literacy: Effective decoding & spelling instruction. Baltimore, Maryland: Brookes Publishing.

Kirk, C. & Gillon, T. G. (2009). Integrated morphological awareness intervention as a tool for improving literacy. Language, Speech, and Hearing Services in Schools, 40, 341-351.

Lyster, S. H. (2002). The effects of morphological versus phonological awareness training in kindergarten on reading development. Reading and Writing: An Interdisciplinary Journal, 15, 261-294.

Moats, L. (2009). Knowledge foundations for teaching reading and spelling. Reading and Writing: An Interdisciplinary Journal. 22, 379-399.

Nunes, T. & Bryant, P. (2006). Improving literacy by teaching morphemes. London: Routlege.

Tomesen, M., & Aarnoutse, C. (1998). Effects of an instructional programme for deriving word meanings. Educational Studies, 24, 107-128.

Tyler, A. A., Lewis, K. E., Haskill, A., & Tolbert, L. C. (2003). Outcomes of different speech and language goal attack strategies. Journal of Speech, Language & Hearing Research, 46, 1077-1094.

Venezky, R. (1967). English orthography: Its graphical structure and its relation to sound. Reading Research Quarterly, 2, 75-105.

Venezky, R. (1999). The American way of spelling. New York: Guilford Press.


  1. Pete, I am going to be first in line to read the whole article when it is published. Thank you! Question: Are these findings applicable to English Language Learners, assuming your analysis included a number of them?

  2. Hey Susan,

    Good question. Unfortunately the studies we found did not allow us to look at the effects for English language learners. I can only comment anecdotally from my work in international schools. English language learners are obviously a major part of the population in these schools, and teachers report to me that teaching groups of words related in meaning and structure to a base (or root) has been a very effective way to build vocabulary for these students. When teaching the word PLEASE, why not teach related words like PLEASURE, PLEASING, UNPLEASANT, and PLEASURABLE at the same time? Activities with a set of morphologically related words like this invite teachers to address a variety issues including the phonology of the EA digraph, conventions with spelling changes due to suffixing, grammatical roles of words marked by suffixes, all while practicing the underlying meaning of a set of words.

    A related area of particular interest for those teaching English to Spanish speaking children is the role of cognates. It may be useful for teachers to draw attention to similarities between English and Spanish words that come from the same Latin root. Teachers may be able to capitalize on knowledge of a Spanish word like VACIA which has the Latin root ‘vacare’ for ‘empty’, to teach English words that grew from this same Latin root such as VACANT, VACATE, VACANCY and VACUUM. By associating those words to the more common (but morphologically unrelated word EMPTY) a whole set of words and shades of meaning are taught at one time.

    I taught in Ecuador for 3 years and was always fascinated how often my students knew the “more academic” word when an English speaker at the same grade would likely use the more common English word. At the time, however, I did not have the word structure knowledge to capitalize on my students’ Spanish to build their English vocabulary more effectively.

  3. Great post, Pete. Susan, thanks for sharing your forum with him!

    The question about teaching morphology to ELL is a little like asking whether fractions and times tables work with ELL students. Morphology is just a fact of English, like fractions are a fact of math -- not a technique that may or may not work. We wouldn't teach ELL math but not fractions, would we? So why teach them words but not morphology?

    I would also like to chime in my anecdotes for English Language Learners and using matrices and word sums to teach vocabulary. This past semester, I taught two Lexicon courses at a university-based English Language Institute, to students who want to pursue university-level studies in the US but need to improve their English.

    The textbooks I used in class both covered the Academic Word List, which has been referenced in Vocablog before. I grouped AWL words by their morphological base, and then further grouped them according to etymology, where I could.

    My students understood, by the end of the term, how to parse such abstract academic Germanic words as ongoing, undertake and straightforward; they had intact strategies for investigating Latin compounds too, like privilege or significant or manipulate. They had the morphological know-how to hypothesize and then prove that the words also had the etymological understanding to find the links between words like hypocrisy and criteria.

    My students were able to make connections between the structure of English and the structure of their own language. Chinese students understood the somewhat logographic nature of Modern English base elements (morphemes). Spanish-speaking students could make connections to similar structures in their own language's rich Latin and Greek lexicon. Arabic speakers understood the bases as something similar to their language's tri-consonantal radicals (JHD in jihad and mujahideen).

    I even had one brilliant blind student whose sole goal for the term was to increase her GRE verbal scores. I had some of the matrices printed in Braille for her, and she was amazed at how they helped her to understand the structure and meaning of words in English.

    Rather than just relying on the AWL textbooks to give an understanding of a word's meaning and usage, I taught students how to use Neil Ramsden's word searcher, plus the online etymology dictionary, along with matrices and word sums, to hypothesize and test their thinking about what words mean, whether words are related, and whether that relationship is morphological (where they share a base as in vision and visual) or etymological (as in vision and view).

    I can't speak to how they did on their TOEFLs this year, but I can attest to the delight and engagement they took in their learning, the evals I have from class, and how much I saw their vocabulary usage and pronunciation improve over the course of the term.

    As a bonus, they became much better spellers!

  4. Thanks Pete and Gina, for sharing your thoughts on ELL instruction. Makes good sense! The matrix in Braille is an intriguing idea.


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