productiveness vs productivity

productiveness and productivity both are nouns.

Word	Noun	Adjective	Verb	Adverb
productiveness	Yes	No	No	No
productivity	Yes	No	No	No

As nouns, productiveness and productivity are synonyms defined as:

productiveness and productivity: the quality of being productive or having the power to produce

productiveness (noun)	productivity (noun)
the quality of being productive or having the power to produce	the quality of being productive or having the power to produce
	(economics) the ratio of the quantity and quality of units produced to the labor per unit of time