The balanced incomplete block design is not suitable for the evaluation of complex interventions

Abstract Objectives In quality of care research, the balanced incomplete block (BIB) design is regularly claimed to have been used when evaluating complex interventions. In this article, we reflect on the appropriateness of using this design for evaluating complex interventions. Study Design and Setting Literature study using PubMed and handbooks. Results After studying various articles on health services research that claim to have applied the BIB and the original methodological literature on this design, it became clear that the applied method is in fact not a BIB design. Conclusion We conclude that the use of this design is not suited for evaluating complex interventions. We stress that, to prevent improper use of terms, more attention should be paid to proper referencing of the original methodological literature.