Variables affect the world in long time frames. The influential Harvard study on human happiness[1] could only have been conducted over the course of a lifetime. Check out The Long Now[2] for a group of people evaluating variables at the 10,000 year time scale.

[1]: http://www.huffingtonpost.com/2013/08/11/how-this-harvard-ps... [2]: http://longnow.org/