"Efficient" = having a high ratio of output to input. Efficient also means means working or producing with a minimum of waste. Examples : "An efficient test engineer wastes no time". "An efficient engine saves gas". "Effective" = producing, or capable of producing, an intended result; or having a striking effect. Example 1: Example : "For rapid long-distance transportation, the jet engine is more effective than a witch's broomstick".

Hi Dima, this question has been asked before so it will help if you read this answer. - > http://www.italki.com/answers/question/93796.htm