If you think plagiarism only happens in high school and college, think again. A new Boston study finds that one in every 20 applications to medical residency programs is plagiarized. The study looked at nearly 5,000 residency application essays to Brigham and Women’s Hospital. That’s considered a nationally representative sample because of the huge number of doctors who apply for residences there: as many as 40% of all applicants across the country. A software program searched the essays for plagiarized material by running them through giant databases of previously published content — and it found that 5.2% of the essays contained material that had already appeared in Web pages, online books or past essays.