What are the best answers for “power to be effective; the quality of being able to bring about an effect”?

effectiveness, effectivity, effectuality, effectualness.

How many letters does the top answer for “power to be effective; the quality of being able to bring about an effect” have?

The most common answer is effectiveness (13 letters).

4 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

effectiveness 13 letters wn-def

power to be effective; the quality of being able to bring about an effect

effectivity 11 letters wn-def

power to be effective; the quality of being able to bring about an effect

effectuality 12 letters wn-def

power to be effective; the quality of being able to bring about an effect

effectualness 13 letters wn-def

power to be effective; the quality of being able to bring about an effect