Single Subject Research

Creswell (2008) describes single-subject research as "the study of single individuals, their observation over a baseline period, and the administration of an intervention. This is followed by another observation after the intervention to determine if the treatment affects the outcome" (p. 647). This definition provides a general idea of what a single-subject design may look like. They can vary by number of participants and design details.




Pullen, P. C., Lane, H. B., Lloyd, J. W., Nowak, R., & Ryals, J. (2005). Effects of explicit instruction on decoding of struggling first grade students: A data-based case study. Education and Treatment of Children, 28, 63-76.



Abstract [with notes added in red]:


Decoding unknown words when reading text is a necessary tool of skilled readers. Beginning readers need repeated opportunities to develop decoding ability. We investigated whether explicitly teaching essential components of beginning reading instruction promoted first graders' skill in decoding pseudowords. We employed a multiple- baseline design [one type of single-subject design that is commonly used] across groups of children to examine the effects of an intervention that included the use of manipulative letters to promote segmenting, blending, sounding out, and spelling skills. We monitored decoding skills by repeatedly measuring reading of pseudowords by 9 first-grade students [single-subject studies use a relatively small number of participants] identified as having incipient reading problems. Findings indicate that each student's skill in decoding increased with the introduction of instruction incorporating explicit decoding practice. These results reveal that teachers can use relatively simple instructional practices to enhance early reading skills. [Single-subject researchers use graphs show their data.]


This is a typical graph that one would see in a single-subject study. Notice that, in this example, each graph represents one participant.