Single-Case Design Experiment

What is it?

Many textbooks said the group comparison. More than two groups, a sample size of more than 30, blah blah… However, if your research participants are tiny, what should you do? For example, what should you do if you want to study the effect of weekly student-led presentations on learning engagement in a graduate course with six students?

Single-case design experiment (SCED) is the intensive study of a single case by repeatedly measuring an outcome while altering the conditions under which the case is being observed (Mariola, lecture note, 2022).

Although many people don’t recognize its logic and benefits, the American Psychology Society considers SCED a robust research technique like a randomized controlled trial (RCT). As mentioned, SCED works with a small number of samples with a highly designed analytical approach. Moreover, the practical condition in education sometimes blocks very controlled experiments in the classroom environment. You can benefit from SCED methodology in this situation.

Basic Logic

  • Logical generalization and statistical generalization are closely related but different. Even if the data size is small, the repeated measure of behaviors/phenomena over time can demonstrate the functional relationship of intervention.
  • Combination with classical statistical techniques is beneficial.

What Should I know?

  • The Introductory level of knowledge about statistical analysis and experiment design (EPSY 530/630 or EEPL 614)
  • Regression basic. An advanced level of SCED is combined with regression modeling techniques.
  • If possible, a basic understanding of non-parametric is recommended but not necessary.

Where can I learn it?

  • ETAP 732 Single-Case Experimental Design and Analysis. It is the only course you can learn the methodology.

Written by YangHyun Kim (

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