effectiveness
US /əˈfek.tɪv.nəs/
UK /əˈfek.tɪv.nəs/

1.
efficacité, efficience
the degree to which something is successful in producing a desired result; success
:
•
The effectiveness of the new policy is still being evaluated.
L'efficacité de la nouvelle politique est toujours en cours d'évaluation.
•
We need to improve the effectiveness of our marketing campaigns.
Nous devons améliorer l'efficacité de nos campagnes de marketing.