Barbara Perry is an expert on presidents’ first years in office, and she gives Donald Trump poor marks so far.

The director of presidential studies at the University of Virginia’s Miller Center of Public Affairs has devised a grading system for presidents based on factors like fulfillment of campaign promises, pre-White House experience, transition to power, and media relations.

Here’s how Trump stacks up to some other recent presidents as he approached the six-month mark on Thursday, according to Perry.

George H.W. Bush: A

George H.W. Bush’s first year received high marks for adherence to campaign promises, as well as his smooth handling of the end of the Cold War.

George W. Bush: A

Perry praises Bush for his commitment to campaign promises, his willingness to reach across the aisle in Congress, and the way he “rose to the occasion” in the wake of 9/11.

Ronald Reagan: A

Perry lauds Reagan for his being “single-minded” and focusing on campaign promises like tax and budget cuts during his first year. He also had a “graceful recovery” from an attempted assassination and nominated the first woman to the Supreme Court—Sandra Day O’Connor.

John F. Kennedy: B-

Perry likens Kennedy to a student who does poorly on a midterm exam but works hard to improve his final grade. He took responsibility for the Bay of Pigs disaster and made changes to his decision making process and policy team; Perry gives him points for “acknowledging and correcting mistakes, which we don’t see on Trump’s part.”

Jimmy Carter: C

Carter faced significant hurdles in his first year, because he “did not understand the Washington media or lobbyists,” and did not work well with Congress, “overloading his legislative agenda” and accomplishing “less than he hoped.”

Bill Clinton: C-

Clinton’s first year was “pretty bad”, due to the Whitewater controversy, his trouble getting an Attorney General in place, and his abandonment of campaign promises.

Donald Trump: D+

Although he gets credit for the swiftness of the appointment of Neil Gorsuch to the Supreme Court and his commitment to campaign promises (e.g., backing out of the Paris agreement), Perry says “the negatives outweigh the positives.” He has been “handicapped” by his utter lack of government or military experience, his “inability to comprehend the levers of power in Washington” and the stalling of his top legislative promises.

Get our Politics Newsletter. The headlines out of Washington never seem to slow. Subscribe to The D.C. Brief to make sense of what matters most. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.