Reading Research for Students with LD: A Meta-Analysis of Intervention Outcomes

NICHCY’s Structured Abstract 32 describes the following

Title | Reading Research for Students with LD: A Meta-Analysis of Intervention Outcomes

Author | Swanson, H.L.

Source Journal of Learning Disabilities, 32, 504-532.

Year Published | 1999

Presents the findings of a meta-analysis involving a sample of children and adolescents who have learning disabilities. Four important findings emerged from the synthesis:

  1. Effect sizes for measures of comprehension were higher when studies included derivatives of both cognitive and direct instruction, whereas effect sizes were higher for word recognition when studies included direct instruction;
  2. Effect sizes related to reading comprehension were more susceptible to methodological variation than studies of word recognition;
  3. The magnitude of ES for word recognition studies was significantly related to samples defined by cutoff scores (IQ > 85 and reading < 25th percentile), whereas the magnitude of ES for reading comprehension studies was sensitive to discrepancies between IQ and reading when compared to competing definitional criteria; and
  4. Instructional components related to word segmentation did not enter significantly into a regression analysis for predicting ES estimates of word recognition beyond an instructional core model, whereas small-group interactive instruction and strategy cuing contributed significant variance beyond a core model to ES estimates of reading comprehension.

Students with learning disabilities (LD) differ in their individual strengths, weaknesses, and learning styles.  Therefore, no one instructional model can be recommended for all. Nevertheless, there may be certain general principles for teaching students with LD that can be adapted to meet each student’s individual needs. Successful interventions include strategies based on these general principles. These strategies can be adapted for different students, different content areas, and different settings. This meta-analysis tries to identify some of the general principles behind effective word recognition and reading comprehension instruction for students, with particular emphasis on the use of Direct Instruction (DI) and Strategy Instruction in designing programs that work.

Research Questions
This meta-analysis examines the effectiveness of different models of word recognition and reading comprehension instruction for students with LD.

Research Design

  • Number of Studies Included | 92
  • Number of Subjects | N/A
  • Years Spanned | 1972-1997

Research Subjects
Children and adolescents with learning disabilities and IQ scores of 85 or above.

Age/Grade of Subjects
Students ranged in grade level from elementary through secondary school. Children in the reading comprehension studies tended to be older (average age = 11.62 years) than children in the word recognition studies (average age = 10.03 years).

Specified Disability
Learning Disabilities (LD)

Students received instructional interventions in word recognition or reading comprehension.

Duration of Intervention

  • Word recognition studies averaged approximately 39 minutes across 39 sessions.
  • Reading comprehension studies averaged approximately 43 minutes across 23 sessions.


  • Interventions that combined direct instruction and strategy instruction were the most effective for teaching reading comprehension.
  • Direct instruction alone was most effective for teaching word recognition.

Combined Effects Size

  • Combined direct instruction and strategy instruction’s impact on reading comprehension: Effect size = 1.15 (large effect)
  • Direct instruction’s impact on word recognition: Effect size = 1.06 (large effect)

Numerous conclusions may be drawn from this research. First, reading comprehension instruction is most effective when teachers use a combination of direct instruction and strategy instruction. In particular, the following components of these two methods appear to make the biggest impact on student performance:

  • Directed response/questioning (e.g., when the teacher asks students questions, guides them in asking their own questions, or engages them in conversation about the subject matter)
  • Controlling task difficulty (e.g., when the teacher uses short activities that move from easy to difficult and provides students with support and demonstration)
  • Elaboration (e.g., when the teacher provides additional information about the subject and/or the steps involved in accomplishing the task)
  • Modeling (e.g., when the teacher demonstrates the steps required to complete the task)
  • Group instruction (e.g., when the teacher provides instructions and interaction in small groups)
  • Strategy cues (e.g., when the teacher reminds students to use strategies or specified steps; when the teacher verbalizes steps or encourages students to “think out loud”)

As noted under Findings, direct instruction has the biggest impact on students’ word recognition skills. The following components are important elements in improving student performance:

  • Sequencing (e.g., when the teacher provides step-by-step instructions for performing a task)
  • Segmentation (e.g., when the teacher breaks down a task into smaller parts)
  • Advanced organizers (e.g., when the teacher provides information and/or objectives before students take on the task, or when the teacher asks students to review material before instruction


* Meta-Analysis | A widely-used research method in which (1) a systematic and reproducible search strategy is used to find as many studies as possible that address a given topic; (2) clear criterion are presented for inclusion/exclusion of individual studies into a larger analysis; and (3) results of included studies are statistically combined to determine an overall effect (effect size) of one variable on another.

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