it doesn't take 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.

• the bottom of the heap
• the bottom of the hour
• the bottom of the ladder
• the boys in blue
• the brains behind
• the brains behind something
• the brass ring
• the bright lights
• the bright side
• the bubble bursts
• the buck stops here.
• the buck stops with
• the buck stops with .
• the buck stops with someone
• the buck stops with someone.
• the bum's rush
• the bush telegraph
• the business end
• the business end of
• the business end of something
• the calm before the storm
• the cards are stacked against
• the cards are stacked against someone
• the cart before the horse
• the casting couch