Rising Grades at Private and Public Schools
Grades: Can't live with 'em, can't live without 'em. Students drive themselves crazy pursuing better grades and professors often deplore the fact that their students focus more on grading than learning. Yet it's necessary to have some standard for student evaluation, and in spite of the push from many schools to deemphasize or eliminate grades, they're not going anywhere.
One of the most persistent controversies in higher education is the unreliable nature of grades. In their recent study, Stuart Rojstaczer and Christopher Healy found articles dating all the way back to 1912 arguing about issues like inter-institutional variability and inflation. The fundamental problem is that if institutions' grading systems aren't transparent, and grading standards aren't consistent between schools, it's difficult to rely on grades as an accurate measure of student performance and ability.
Yet grades continue to have enormous importance for most college students. Grades can make or break their ability to get into a good graduate or professional school. Even students who don't plan to pursue further education rely on the honors that come with good grades to polish their resumes. This is where grade inflation comes in: Out of a desire to help their students, professors respond to this pressure by lowering their grading standards, which artificially inflates their students' grades.
Professors Stuart Rojstaczer (Duke University) and Christopher Healy (Furman University) recently published a study on current and historical grading patterns in American higher education. They gathered contemporary grading data from over 160 colleges and universities with a combined enrollment of over two million students, as well as historical grading data from over 80 schools. As the graph below indicates, they found that grades have gone through several distinct periods of inflation over the past century - there was a gentle rise in the 1930s and 1940s, then a rapid rise in the 1960s and finally a steady rise that began in the 1980s and is still going.
It's difficult to pinpoint the causes of each cycle of grade inflation. The rise in the 1960s is typically correlated with the social turmoil of the Vietnam War, but the reason for the current period is still up for debate. Rojstaczer and Healy point out that it's almost certainly not due to a genuine increase in student achievement. Students' test scores haven't increased and there's evidence that students are, in fact, becoming less literate and less engaged in their studies. The authors do hypothesize that the common practice of student-based teacher evaluations may have contributed. Regardless of the reasons, grading standards in the U.S. are currently lower than they've ever been before.
Average GPA over the time period 1930-2006 as a function of school type.
Figure 1 from Grading in American Colleges and Universities.
However, not all schools inflate their grades equally. In their historical analysis, Rojstaczer and Healy noticed that private and public schools began to diverge in their grading practices during the 1950s. Once again, the reasons aren't certain, but the authors suggest that it's related to the (then new) practice of graduate and professional schools using quantitative measures for evaluating student performance. This marked the beginning of the transition of grades from an internal measure of student performance to a marker for external evaluation. Private schools seemed more apt than public schools to respond to this pressure and raise grades in order to preserve the appearance of selectivity - in order to prove they were better schools, they had to 'waive around' better grades.
In fact, Rojstaczer and Healy found that, over time, colleges and universities have developed an 'ad hoc' national grading scale based on school selectivity. Although there's no explicit mandate dictating that schools grade a certain way, the authors' data indicates that current grades at any institution can be predicted based on one of two formulae using selectivity and SAT scores. For the formulae, selectivity is defined as the percentage of students who graduated in the upper 10% of their high school class, the average of the percentage of students with high school GPAs above 3.75 and the percentage of student applicants who are rejected. The predictive equations show that private schools grade 0.1 to 0.2 points higher on a 4.0 scale.
There's no evidence that private schools necessarily provide students with a better education than public schools. The 'generous grading' at private schools thus confers an even greater advantage to students who are already more likely to come from wealthy and educated families. And this advantage perpetuates itself - students from private schools dominate the country's top graduate and professional schools (think law schools, medical schools, even business schools), which tend to assign extra prestige to applicants from selective private schools, regardless of the evidence of grade inflation.
Differences between the average GPA predicted by both SAT score and selectivity as a function of school type.
Figure 2 from Grading in American Colleges and Universities.
Of course, not all schools follow the predicted patterns. When applying their formulae, Rojstaczer and Healy found that private liberal arts colleges tend to vary considerably, particularly on the low end of the scale, and that public flagship universities tend to grade higher relative to other public schools.
The authors also found that science and engineering schools grade on average 0.15 points lower than their peers, which seemed surprising until they broke down grading patterns by discipline. Nationally, at all types of colleges and universities, science departments grade an average of 0.4 points lower than humanities departments and 0.2 points lower than social sciences. Engineering departments, on the other hand, grade much higher than science departments, but not enough to balance things out. Because students at science and engineering schools take more science classes, they end up with a lower GPA. Rojstaczer and Healy point out that this may lead to the poor retention rates at these schools, and confer an unintended disadvantage to their students after graduation.
Rojstaczer and Healy hope to use their data to promote greater transparency in our nation's grading systems. They feel that many of the inequalities created by grade inflation could be reduced if graduate schools, employers and others who evaluate college graduates had access to side-by-side comparisons of how institutions grade. To that end, they've launched a public online database of grades at GradeInflation.com. The website features several detailed breakdowns of their data, including the summary graph above, which shows the steady national increase in GPA trends since the early 1990s.
Their project, however, is not without its critics. Clifford Adelman, a senior associate at the Institution for Higher Education Policy, argues that Rojstaczer and Healy relied on selective measures for their study. Adleman claims that, in direct opposition to their results, longitudinal data from the Department of Education's National Center for Education Statistics does not show a trend of grade inflation over the past few decades.
Even with the accuracy of Rojstaczer and Healy's analysis in question, increasing transparency in schools' grading systems is a worthy goal. Greater transparency could help students and evaluators alike make more accurate decisions about the quality of their education.