College grade inflation is in the news this week following the revelation that the most common grade given to Harvard University undergraduates is an "A."

Two of the biggest questions around grade inflation are a) "Are higher grades being given out to college students?" and b) "If so, why?"

The first question has a simple answer — yes. A 2011 New York Times article on the subject cites research from "grade inflation chroniclers extraordinaire" Stuart Rojstaczer and Christopher Healy, noting that "the share of A grades awarded has skyrocketed over the years." You can check out Rojstaczer's website www.gradeinflation.com for a more detailed look.

There have been a lot of reasons cited as to why this is, but the one probably repeated most frequently is that during the Vietnam War college professors started handing out higher grades to ensure that students wouldn't fail out and be drafted. In a 2002 paper on grade inflation, Rojstaczer and Healy quote a University of Florida professor, who says:

The upward shift started in the jungles of Vietnam, when those of us now at the full-professor level were safely in graduate school. We were deferred by virtue of being in school, which wasn't fair and we knew it. So when grading time came, and we knew that giving a C meant that our student (who deserved a D) would go into the jungle, we did one better and gave him a B.

Additionally the paper argues that general campus unrest in the late 1960s led to "particularly large inflationary leaps in grades." Following the U.S. Army invasion of Cambodia, Rojstaczer and Healy write, Harvard students "were allowed to designate ex post facto whether they preferred a letter grade or pass-fail. The effects of this decision on GPA's are obvious."

While this has become the dominant reasoning for the grade inflation boom of the 1960s that has continued to today, it may not apply equally to all universities. For instance, Yale University says that their grading — which now skews high — remained steady during the period of the war, and only increased after academic departments stopped distributing annual reports on students' grades.