Explanation Rational Expectations I am struggling understanding the concept of rational expectations. Can someone explain in simple words the concept of rational expectations? Does someone know a good (online) source explaining rational expectations?
The concept of rational expectations can indeed be confusing. 

One of the nicest pieces that I read online on rational expectations is the following: 

https://economictheoryblog.com/2012/05/18/rational-expectations

It very nicely describes the concept of rational expectations in very simple words. 

The most important thing one needs to understand is that rational expectations do not imply that all people act optimal under all circumstances, it rather implies that people behave optimally given the information they have.