Tony Lee, publisher of CareerCast.com, says the profession has always been ranked among the worst jobs due to low pay, high levels of stress from working under deadlines, a poor hiring outlook and the requirement to be on duty twenty-four hours a day, seven days a week.

FORBES: The Best And Worst Jobs For 2013

The paper suggests he was under stress to finish his dissertation while working as a member of parliament.

BBC: German minister denies plagiarism on PhD thesis