contributive vs effective

contributive

adj
  • Tending to contribute; making a contribution 

effective

adj
  • Producing a decided or decisive effect. 

  • approximate; Not describing the fundamental dynamic changes in some system as they happen. 

  • Efficient, serviceable, or operative, available for useful work. 

  • Having no negative coefficients. 

  • Having the power to produce a required effect or effects. 

  • Actually in effect. 

noun
  • a soldier fit for duty 

How often have the words contributive and effective occurred in a corpus of books? (source: Google Ngram Viewer )