Theorists have examined the value of repetition for soft-sell versus hard-sell messages, in order to determine their relative efficacy.

Little is known of the relative efficacy and toxicity of different strains.

Consider, by analogy, the relative efficacy of ways to deal with water-borne disease.

Although this may be used in clinical practice, there is little evidence for the relative efficacy or adverse effects of this strategy.

The relative efficacy of various types of prior belief-defense in producing immunity against persuasion.

We need to learn the relative efficacy and safety of new drugs as accurately and quickly as possible.

Theorists have examined the value of repetition for hard sell versus soft sell messages to determine their relative efficacy.

The relative efficacy of magnetorheological dampers to active and passive control strategies is usually comparable.

The relative efficacy of this approach versus the standard approach would require further investigation.

At present (as of 2008), a controversy exists in the scholarly literature regarding grief therapy's relative efficacy and the possible harm from it (iatrogenesis).