Understanding Efficacy vs. Efficiency: Definitions, Usage, and Key Differences

Understanding the Difference Between Efficacy and Efficiency

History of the Words

The word efficacy comes from the Latin word “efficacia,” which means power to produce effects. The word efficiency is from the Latin word “efficientia,” meaning the ability to accomplish something with the least waste of time and effort.

How to Use Them

– Efficacy means how well something works. It tells us if something does what it is supposed to do.
– Efficiency means how well something uses time, energy, or resources. It shows us if something is done in the best way possible with little waste.

Trick to Remember the Difference

Think about a light bulb. If a light bulb brightens your room, it has efficacy. If it uses very little electricity to brighten your room, it has efficiency.

Example Sentences for Efficacy

1. The efficacy of the new medicine is very high.
2. They tested the efficacy of the teaching methods.
3. We need to check the efficacy of the bug spray.
4. The efficacy of the alarm system keeps our house safe.
5. Doctors study the efficacy of treatments before giving them to patients.

Example Sentences for Efficiency

1. This car has good fuel efficiency.
2. They improved the efficiency of the factory.
3. We need to work on the efficiency of our team.
4. The efficiency of this computer saves us a lot of time.
5. Learning to type faster increases your work efficiency.

Summary

To sum up, efficacy is all about how well something works and does its job. Efficiency is about how well something uses time, energy, or resources without wasting them. Remember, if it works, it’s efficacy. If it works well and fast, it’s efficiency.