How do you use efficasy in a sentence?

Here are some examples of how to use "efficacy" in a sentence:

* Formal: The efficacy of the new drug was proven in clinical trials.

* Informal: We're still debating the efficacy of this marketing campaign.

* Emphasis on comparison: The efficacy of this treatment far surpasses the previous methods.

* Questioning efficacy: The study raises questions about the efficacy of traditional methods.

Remember that "efficacy" refers to the ability of something to produce a desired result.