The phrase 'A for Effort' is used when recognizing that someone tried hard to accomplish something although they might not have been successful.
Example of Use: “The cake didn’t turn out like she had planned, but I give her an A for effort!”
You get an 'A for effort' when you do your best, even though your work might not be top-notch. We know that letter grades with “A” as the highest attainable grade were first used in the USA in the latter part of the 19th century. The origin of the idiom 'A for effort' isn’t attributed to any one person or school; it has been in use since the 1940s.