As nouns the difference between validness and effectivity
is that validness is the state of being valid while effectivity is (uncountable) the ability or power to be effective.
validness
English
Noun
(-)
the state of being valid
effectivity
English
Noun
(uncountable) The ability or power to be effective.
(countable) A measure of the effectiveness of something.
Related terms
* effect
* effective
* effectiveness
* effector
* effectual
* effectuate
* efficacious
* efficacity
* efficacy
* efficiency
* efficient
See also
* effectively