Understanding and Supporting Poor Readers. A Theoretical, Clinical, and Meta-Analytic Investigation of Decoding and Text Comprehension Interventions

Learning to read is a fundamental developmental ability; yet, many children experience persistent difficulties that interfere with their academic achievement and daily life. Among reading disorders, children with decoding disorders present slow and inaccurate reading, whereas those with comprehension disorders struggle to extract meaning from text. This dissertation examined these profiles by integrating theoretical, empirical, and methodological perspectives. Chapter 1 reviewed theories of reading and evidence on interventions. It highlighted that the effectiveness of interventions depends on the skills and outcomes targeted and the way programs are delivered, showing that decoding-focused and comprehension-focused approaches can work in different but complementary ways. Chapter 2 reported a longitudinal quasi-experimental study evaluating a technology-based intervention for Italian children with dyslexia using secondary clinical data. Results indicated short-term improvements in reading speed and accuracy beyond natural developmental growth. Treatment intensity (longer session duration) predicted greater speed gains, and children with more severe initial difficulties showed larger error reductions, emphasizing the importance of tailoring interventions. Chapter 3 presented a systematic review and meta-analysis of interventions for poor comprehenders. Findings revealed moderate effects for reading comprehension, maintained at follow-up. Interventions produced larger gains for poor than for good comprehenders, highlighting the benefits of targeted comprehension training. However, no consistent transfer was observed to vocabulary, inference making, working memory, or decoding, although oral comprehension showed preliminary gains. Finally, moderator analyses showed that effects were greater on researcher-developed than on standardized measures, and that teacher-delivered interventions were more effective than other methods. This dissertation highlights that decoding and comprehension require distinct but coordinated interventions. By using clinical data, it captures heterogeneity and individual differences, underscoring the importance of tailored support delivered in ecological contexts. Overall, it shows how theory, research, and practice inform one another, leading to more effective and accessible interventions for children with reading difficulties.