What is required for an equivalence trial to show clinically unimportant differences between treatments?

In an equivalence trial, the primary goal is to demonstrate that the effects of two treatments are sufficiently similar, within a pre-specified range of acceptable differences known as the equivalence margins. These margins are crucial because they define the boundaries within which the treatments can be considered equivalent in terms of their clinical effects.

Establishing well-defined upper and lower equivalence margins allows researchers to assess whether the difference in outcomes between the treatments falls within these boundaries. If the treatment difference lies outside of these margins, it would imply that the treatments are not equivalent, which is contrary to the objective of the trial. The selection of these margins is based on clinical judgment and prior knowledge about the treatments being assessed, ensuring that any observed differences are clinically unimportant.

The other choices do not serve the purpose of demonstrating equivalence. Superiority testing focuses on proving that one treatment is better than another rather than showing similarity. While having a large sample size may enhance the study's power and accuracy, it does not directly address the requirement of defining equivalence margins. A list of adverse events is important for safety considerations but does not contribute to the determination of equivalence. Thus, the well-defined equivalence margins are essential for successfully demonstrating that the differences between treatments are not