There is a new Best Evidence in Brief which mentions this time research in which a Belgian scientist was involved:
Ariane Baye from the University of Liege and Cynthia Lake and colleagues from our Center for Research and Reform in Education have updated their paper Effective Reading Programs for Secondary Students. Their review focuses on 73 studies that used random assignment (n=66) or high-quality quasi-experiments (n=7) to evaluate outcomes of 55 programs on widely accepted measures of reading.The authors found that specific programs using one-to-one, small-group tutoring, and cooperative learning showed positive outcomes, as did a small number of programs emphasizing social-emotional learning, technology, or teaching of metacognitive strategies. Benchmark assessments did not affect reading outcomes. Leaving aside tutoring and benchmarks, programs that provide additional instructional time (usually, a daily extra period) were no more effective than programs that did not provide extra time.
The findings suggest that secondary readers benefit more from engaging and personalized instruction than from additional time on supplemental courses.