determining factor vs determinative

determining factor and determinative both are nouns.

Word	Noun	Adjective	Verb	Adverb
determining factor	Yes	No	No	No
determinative	Yes	Yes	No	No

As nouns, determining factor and determinative are synonyms defined as:

determining factor and determinative: a determining or causal element or factor

Other synonyms of determining factor include causal factor, determinant, determiner.

determining factor (noun)	determinative (noun)
a determining or causal element or factor	a determining or causal element or factor
an argument that is conclusive	one of a limited class of noun modifiers that determine the referents of noun phrases

determining factor (adjective)	determinative (adjective)
	having the power or quality of deciding