Treatment outcomes for students with learning disabilities: how important are internal and external validity?

@article{Simmerman2001TreatmentOF,
  title={Treatment outcomes for students with learning disabilities: how important are internal and external validity?},
  author={Sue Simmerman and Heather L. Swanson},
  journal={Journal of learning disabilities},
  year={2001},
  volume={34 3},
  pages={
          221-36
        }
}
This study analyzed the magnitude of experimental intervention outcomes as a function of violations in internal and external validity for studies that included students with learning disabilities. The results indicated that treatment outcomes were significantly affected by the following violations: teacher effects, establishing criterion levels of instructional performance, reliance on experimental measures, using different measures between pretest and posttest, using a sample heterogenous in… CONTINUE READING