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In carrying out its analysis of the extant research in reading comprehension, the NRP noted three predominant themes in the research on the development of reading comprehension skills.

  • First, reading comprehension is a complex cognitive process that cannot be understood without a clear description of the role that vocabulary development and vocabulary instruction play in the understanding of what has been read.
  • Second, comprehension is an active process that requires an intentional and thoughtful interaction between the reader and the text.
  • Third, the preparation of teachers to better equip students to develop and apply reading comprehension strategies to enhance understanding is intimately linked to students’ achievement in this area.

Because these three themes serve as the foundation for understanding how best to help teachers develop students’ comprehension abilities, the extant research relevant to vocabulary instruction, to text comprehension instruction, and to the preparation of teachers to teach reading comprehension strategies was examined in detail by the NRP.

The major findings and determinations of the Panel for each of these three sub areas are provided next.

Vocabulary instruction

The importance of vocabulary knowledge has long been recognized in the development of reading skills. As early as 1924, researchers noted that growth in reading power means continuous growth in word knowledge (Whipple, 1925). Vocabulary is critically important in oral reading instruction.

There are two types of vocabulary — oral and print. A reader who encounters a strange word in print can decode the word to speech. If it is in the reader’s oral vocabulary, the reader will be able to understand it. If the word is not in the reader’s oral vocabulary, the reader will have to determine the meaning by other means, if possible. Consequently, the larger the reader’s vocabulary (either oral or print), the easier it is to make sense of the text.

To determine how vocabulary can best be taught and related to the reading comprehension process, the NRP examined more than 20,000 research citations identified through electronic and manual literature searches.

From this set, citations were removed if they did not meet prespecified criteria: if they were not reports of research, if they were not reporting experimental or quasi-experimental studies, if they were not published in English, or if they dealt exclusively with learning disabled or other special populations, including second-language learners. Comprehensive review of the remaining set of studies according to the NRP review criteria identified 50 studies for further evaluation.

Further analysis and coding of these studies indicated that a formal meta-analysis could not be conducted because there was a small number of research studies in vocabulary instruction dealing with a relatively large number of variables. There are recent published meta-analyses for some selected variables, and it was decided not to duplicate those efforts. Also, a substantial amount of published research on vocabulary instruction did not meet NRP research methodology criteria.

Because the Panel wanted to glean as much information as possible from the studies identified in the searches, the vocabulary instruction database was reviewed for trends across studies, even though formal meta-analyses could not be conducted. Fifty studies dating from 1979 to the present were reviewed in detail. There were 21 different methods represented in these studies.

Findings and determinations

The studies reviewed suggest that vocabulary instruction does lead to gains in comprehension, but that methods must be appropriate to the age and ability of the reader. The use of computers in vocabulary instruction was found to be more effective than some traditional methods in a few studies. It is clearly emerging as a potentially valuable aid to classroom teachers in the area of vocabulary instruction.

Vocabulary also can be learned incidentally in the context of storybook reading or in listening to others. Learning words before reading a text also is helpful.

Techniques such as task restructuring and repeated exposure (including having the student encounter words in various contexts) appear to enhance vocabulary development. In addition, substituting easy words for more difficult words can assist low-achieving students.

The findings on vocabulary yielded several specific implications for teaching reading. First, vocabulary should be taught both directly and indirectly. Repetition and multiple exposures to vocabulary items are important. Learning in rich contexts, incidental learning, and use of computer technology all enhance the acquisition of vocabulary. Direct instruction should include task restructuring as necessary and should actively engage the student. Finally, dependence on a single vocabulary instruction method will not result in optimal learning.

While much is known about the importance of vocabulary to success in reading, there is little research on the best methods or combinations of methods of vocabulary instruction and the measurement of vocabulary growth and its relation to instruction methods.

Text comprehension instruction

Comprehension is defined as “intentional thinking during which meaning is constructed through interactions between text and reader” (Harris & Hodges, 1995). Thus, readers derive meaning from text when they engage in intentional, problem solving thinking processes. The data suggest that text comprehension is enhanced when readers actively relate the ideas represented in print to their own knowledge and experiences and construct mental representations in memory.

The rationale for the explicit teaching of comprehension skills is that comprehension can be improved by teaching students to use specific cognitive strategies or to reason strategically when they encounter barriers to understanding what they are reading. Readers acquire these strategies informally to some extent, but explicit or formal instruction in the application of comprehension strategies has been shown to be highly effective in enhancing understanding. The teacher generally demonstrates such strategies for students until the students are able to carry them out independently.

The literature search identified 453 studies that addressed issues and topics relevant to text comprehension since 1980. Studies published between 1970 and 1979 were added if they were of particular relevance, resulting in 481 studies that were initially reviewed. Of these, 205 studies met the general NRP methodological criteria and were then classified into instructional categories based on the kind of instruction used.

Application of the more specific review criteria precluded formal meta-analyses because of the large variation in methodologies and implementations used. The Panel found few research studies that met all NRP research methodology criteria. Nevertheless, the Panel employed the NRP criteria to the maximum extent possible in its examination of this body of literature.

In its review, the Panel identified 16 categories of text comprehension instruction of which seven appear to have a solid scientific basis for concluding that these types of instruction improve comprehension in non-impaired readers. Some of these types of instruction are helpful when used alone, but many are more effective when used as part of a multiple-strategy method. The types of instruction are:

  • Comprehension monitoring , where readers learn how to be aware of their understanding of the material
  • Cooperative learning, where students learn reading strategies together
  • Use of graphic and semantic organizers (including story maps), where readers make graphic representations of the material to assist comprehension
  • Question answering, where readers answer questions posed by the teacher and receive immediate feedback
  • Question generation, where readers ask themselves questions about various aspects of the story
  • Story structure, where students are taught to use the structure of the story as a means of helping them recall story content in order to answer questions about what they have read
  • Summarization, where readers are taught to integrate ideas and generalize from the text information

Findings and determinations

In general, the evidence suggests that teaching a combination of reading comprehension techniques is the most effective. When students use them appropriately, they assist in recall, question answering, question generation, and summarization of texts. When used in combination, these techniques can improve results in standardized comprehension tests.

Nevertheless, some questions remain unanswered. More information is needed on ways to teach teachers how to use such proven comprehension strategies. The literature also suggests that teaching comprehension in the context of specific academic areas — for example, social studies — can be effective. If this is true of other subject areas, then it might be efficient to teach comprehension as a skill in content areas.

Questions remain as to which strategies are most effective for which age groups. More research is necessary to determine whether the techniques apply to all types of text genres, including narrative and expository texts, and whether the level of difficulty of the texts has an impact on the effectiveness of the strategies. Finally, it is critically important to know what teacher characteristics influence successful instruction of reading comprehension.

Teacher preparation and comprehension strategies instruction

Teaching reading comprehension strategies to students at all grade levels is complex. Teachers not only must have a firm grasp of the content presented in text, but also must have substantial knowledge of the strategies themselves, of which strategies are most effective for different students and types of content and of how best to teach and model strategy use.

Research on comprehension strategies has evolved dramatically over the last two decades. Initially, investigators focused on teaching one strategy at a time; later studies examined the effectiveness of teaching several strategies in combination. However, implementation of this promising approach has been problematic. Teachers must be skillful in their instruction and be able to respond flexibly and opportunistically to students’ needs for instructive feedback as they read.

The initial NRP search for studies relevant to the preparation of teachers for comprehension strategy instruction provided 635 citations. Of these, only four studies met the NRP research methodology criteria. Hence, the number of studies eligible for further analysis precluded meta-analysis of the data derived from these investigations. However, because there were only four studies, the NRP was able to review them in detail. The studies investigate two major approaches: Direct Explanation and Transactional Strategy Instruction.

The Direct Explanation approach focuses on the teacher’s ability to explain explicitly the reasoning and mental processes involved in successful reading comprehension. Rather than teach specific strategies, teachers help students

  • To view reading as a problem solving task that necessitates the use of strategic thinking
  • To learn to think strategically about solving comprehension problems

For example, teachers are taught that they could teach students the skill of finding the main idea by casting it as a problem solving task and reasoning about it strategically.

Transactional Strategy Instruction also emphasizes the teacher’s ability to provide explicit explanations of thinking processes. Further, it emphasizes the ability of teachers to facilitate student discussions in which students collaborate to form joint interpretations of text and acquire a deeper understanding of the mental and cognitive processes involved in comprehension.

Findings and determinations

The four studies (two studies for each approach) demonstrated that teachers could be instructed in these methods. Teachers required instruction in explaining what they are teaching, modeling their thinking processes, encouraging student inquiry, and keeping students engaged.

Data from all four studies indicated clearly that in order for teachers to use strategies effectively, extensive formal instruction in reading comprehension is necessary, preferably beginning as early as preservice.

More research is needed to address the following questions. Which components of teacher preparation are most effective? Can reading comprehension strategies be successfully incorporated into content area instruction? How can the effectiveness of strategies be measured in an optimal manner? Can strategies be taught as early as first and second grade, when children also are trying to master phonics, word recognition, and fluency? How can teachers be taught to provide the most optimal instruction?


Excerpted from: National Reading Panel. (April, 2000). Report of the National Reading Panel. Teaching Children to Read: An Evidence-Based Assessment of the Scientific Research Literature on Reading and Its Implications for Reading Instruction. National Institute of Child Health and Human Development.

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