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Efficiency refers to those words and images which emphasize ability and effectiveness of the product or service: Does it work? Can it do the job?

Strength and effort are often related to efficiency.

In one sense, all persuaders promise, "I am the means to the end, the agent of the effect."

But, some ads especially emphasize that the product or service is the cause of a desired effect. Medicines, for example, to stop pain or cure ills, cosmetics to enhance beauty. FDA regulations require drug ads to avoid absolute generalities and to use qualifiers ("helps... may relieve ... some") about the efficiency of a medicine.