competent vs effective

competent

adj
  • Having sufficient skill, knowledge, ability, or qualifications. 

  • Resistant to deformation or flow. 

  • Having jurisdiction or authority over a particular issue or question. 

  • Adequate for the purpose. 

  • Permeable to foreign DNA. 

effective

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

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

  • Having no negative coefficients. 

  • Producing a decided or decisive effect. 

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

  • Actually in effect. 

noun
  • a soldier fit for duty 

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