Word: efficacy (noun)

Associations

"Efficacy" means the ability to produce a desired or intended result. It is often used in formal contexts like science, medicine, or business to talk about how well something works.

• In medicine: "The efficacy of the new drug was proven in clinical trials." This means the drug works well.
• In business: "We need to test the efficacy of our marketing strategy." This means checking if the strategy brings good results.
• In education: "The efficacy of this teaching method is supported by research." This means the method helps students learn effectively.

A similar word is "effectiveness." The difference is that "efficacy" usually refers to how well something works under ideal or controlled conditions (like in a lab), while "effectiveness" refers to how well it works in real life or everyday situations.

Substitution

You can replace "efficacy" with:

• effectiveness (more general, real-world use)
• success (more casual, focuses on achieving goals)
• potency (often used for drugs or chemicals, meaning strength)

Example: "The efficacy of the vaccine is high." → "The effectiveness of the vaccine is high."

Deconstruction

The word "efficacy" comes from Latin:

• Root: "efficax" meaning "effective, efficient"
• Prefix: "ef-" (variant of "ex-") meaning "out"
• Root: "facere" meaning "to do or make"
• Suffix: "-acy" forming a noun that means quality or state

So, "efficacy" literally means the quality of doing or producing an effect.

Inquiry

• Can you think of a product or method you have used where you noticed its efficacy?
• How would you explain the difference between efficacy and effectiveness to a friend?
• In what situations is it important to measure efficacy rather than just success?