# effectiveness

/ˈifɛktɪvnəs/ (US) · /ɪfˈɛktɪvnəs/ (UK)

Source: https://englishreference.com/word/effectiveness
Updated: 2026-06-19

## Senses

### 1. producing results

noun · CEFR B2

how well something works to get the result you planned.

For teachers: the quality of being successful in producing a desired or intended result. Uncountable in its general sense, though countable when referring to specific instances or measures.

- The doctors are still testing the effectiveness of the new drug.
- The study aims to evaluate the long-term effectiveness of the government's new environmental policies on urban air quality.

### 2. military/legal force

noun · CEFR C1 · Formal · Technical

the state of being in operation or having power.

For teachers: the state of being in effect or having the power to produce a required outcome, particularly regarding legal or military force.

- The law will reach full effectiveness starting next January.
- The treaty's effectiveness was compromised by the lack of a clear enforcement mechanism for member states that failed to comply.

## Examples

- The doctor checked the effectiveness of the new medicine.
- The marketing team is currently measuring the effectiveness of their social media campaign by tracking website traffic.
- While the policy was popular with the public, its long-term effectiveness remained a subject of intense debate among economists who questioned its impact on inflation.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.