Source : Webster's Revised Unabridged Dictionary (1913)

Contributive \Con*trib"u*tive\, a.
   Contributing, or tending to contribute. --Fuller.

Source : WordNet®

contributive
     adj : tending to bring about; being partly responsible for;
           "working conditions are not conducive to productivity";
           "the seaport was a contributing factor in the growth of
           the city"; "a contributory factor" [syn: {conducive}, {contributing(a)},
            {contributory}, {tributary}]