Have you ever thought about the difference between effective and efficient?
Use effective when you want to say that something gives the result that was intended. Effective tells us whether something has been done, not how it was done. The focus is on the result.
Those pills are really effective – my headache disappeared in less than twenty minutes.
The manager’s speech was short but remarkably effective.
Being effective can also mean officially start.
The new regulation is effective from 1 October.
Use efficient to say that somebody or something works well without wasting time, money or energy. Efficient tells us how something was achieved. The focus is on the process, on minimising cost or waste.
We are installing a much more efficient cooling system.
She is a very efficient salesperson.
To sum up, effective is goal-oriented and focuses on the ability to produce a wanted result; efficient focuses on how little was wasted to produce the result. Or, to quote Peter Drucker, being effective means doing the right things, being efficient means doing things right.
An efficient company will do things at a lower cost (with higher profit), but it must also meet the customers’ requirements by being effective.
The corresponding nouns are effectiveness and efficiency.
If you have seven minutes to spare, here is a video explaining the difference between effective and efficient. And here you can read about affect and effect.