it doesn't take a rocket scientist to do something
alsoyou don't have to be a rocket scientist to do something
it is easy to understand something It doesn't take a rocket scientist to understand that fewer and fewer schools can afford to maintain competitive athletic programs.
Usage notes: sometimes used in the form it's not rocket science: A five year old could put this puzzle together - it's not rocket science.
if you say that it doesn't take a rocket scientist to understand something, you mean that it is obvious (usually + to do sth) Drugs equals crime. It doesn't take a rocket scientist to figure that one out.