efficacy

efficacy — noun

1. the degree to which a method, product, or approach succeeds at doing what it was

1.名詞C1
釋義

the degree to which a method, product, or approach succeeds at doing what it was designed or expected to do

例句

The new teaching method's efficacy was clear when test scores rose across the school.

collocation: efficacy of [method/system/program]

Diya questioned the recycling system's efficacy after learning most waste went to landfill.

collocation: question the efficacy of

同義詞
  • effectiveness

    the most common, everyday equivalent; 'efficacy' is more formal

  • utility

    focuses more on practical usefulness than ability to produce results

  • potency

    usually refers to strength of a chemical, drug, or argument; narrower scope

反義詞

文法句型

the efficacy of [something]

用法筆記

Typically uncountable and used in formal or academic writing rather than everyday conversation. Often paired with a prepositional phrase beginning with 'of' to specify what is being evaluated.

常見錯誤

❌We measured the efficiency of the new marketing campaign.' (when the question is whether it worked)
✅We measured the efficacy of the new marketing campaign.
💡'efficiency' is about doing things without waste; 'efficacy' is about producing the desired result.

2. a measure of how successfully a medical treatment, drug, or therapy performs whe

2.名詞C2
釋義

a measure of how successfully a medical treatment, drug, or therapy performs when tested in a controlled research setting, before or after it reaches patients

例句

Clinical trials test the efficacy of new vaccines before they reach the public.

collocation: clinical efficacy

The drug showed high efficacy in treating the disease during the initial lab tests.

collocation: show high efficacy in treating

同義詞
  • effectiveness

    used more broadly in everyday medical talk; 'efficacy' is the technical research term

  • potency

    emphasises the strength or power of a drug at a given dose, rather than overall success rate

文法句型

the efficacy of [drug/treatment/vaccine]

safety and efficacy

用法筆記

Frequently appears alongside 'safety' in the fixed phrase 'safety and efficacy'. Subject of evaluation is typically a treatment, drug, vaccine, or therapy. Common in regulatory and pharmaceutical contexts.

常見錯誤

❌The drug showed high efficiency in the clinical trial.
✅The drug showed high efficacy in the clinical trial.
💡In medical and scientific contexts, 'efficacy' (not 'efficiency') is the correct term for how well a treatment works under controlled conditions.