What are the differences between 效果 and 效应? Which of the following sentences is correct, or are both correct? Why?

虽然学校采取了一些措施，但是没有什么效果.

虽然学校采取了一些措施，但是没有什么效应.
效果: result; effect

效应: effect 


  1.虽然学校采取了一些措施，但是没有什么效果. 2.虽然学校采取了一些措施，但是没有什么效应.


Both 没有效果 and 没有效应 are correct if you want to say "no effect" 

When you want to say "result" then you must say "效果"

Example: 

"US tax reform has not achieved the expected results" = "美国税改并未达到预期的效果" 

"US tax reform has not created the expected effect" = "美国税改并未产生预期的效应" 

Since 效果 has meaning other than 'effect' We usually translate 'effect' as 效应

As user 3306356's answer stated:   'the butterfly effect' is translated as 蝴蝶效应 (the butterfly effect) instead of 蝴蝶效果(the butterfly effect/result)