Evidence and Practice

When and how to use factorial design in nursing research

Why you should read this article: • Factorial design is underused in nursing research • Factorial design is a cost-effective way to examine different interventions simultaneously • Factorial design is the only design that enables researchers to study and understand how interventions interact Background Quantitative research designs are broadly classified as being either experimental or quasi-experimental. Factorial designs are a form of experimental design and enable researchers to examine the main effects of two or more independent variables simultaneously. They also enable researchers to detect interactions among variables. Aim To present the features of factorial designs. Discussion This article provides an overview of the factorial design in terms of its applications, design features and statistical analysis, as well as its advantages and disadvantages. Conclusion Factorial designs are highly efficient for simultaneously evaluating multiple interventions and present the opportunity to detect interactions amongst interventions. Such advantages have led researchers to advocate for the greater use of factorial designs in research when participants are scarce and difficult to recruit. Implications for practice A factorial design is a cost-effective way to determine the effects of combinations of interventions in clinical research, but it poses challenges that need to be addressed in determining appropriate sample size and statistical analysis.