This page provides an overview of some of the most common types of single-case designs used in research and practice.
N-of-1 Trial Design
N-of-1 trials are multi-cycle, double-blind, individualised randomised controlled trials (RCTs). A single patient provides their own data in response to treatment and comparator, which is randomised within 3 or more cycles of paired periods (e.g. BA AB AB). The patient is their own control. Symptoms are recorded using validated outcome measures. After the data is analysed, individual reports are sent to doctor and patient for discussion about whether the treatment works for them.
Multiple Baseline Design
In this design the start of treatment conditions is staggered (started at different times) across individuals. Because treatment is started at different times it strengthens conclusions because changes observed in the outcome measured are likely due to the treatment implemented rather than to an external factor. By gathering data from many individuals , inferences can be made about the likelihood that the measured effect generalises to a larger population.
N-of-1 Observational Design
N-of-1 observational designs (also known as single-case observational designs) involve repeated measurement of an outcome (e.g., pain) in an individual over time, without any intervention, to draw conclusions about naturally-occurring patterns and outcome predictors which can provide insight into potential intervention strategies.