This is a rather interesting article that first appeared in the APS News. It examines that effect of using a GRE cutoff score as a basis for graduate admission in physics, and how this may contribute to a reduced diversity for American students.
Justifying using the GRE becomes significantly more complicated, however, when the test results are dissected by race and gender. The figure plots QGRE scores by race/ethnicity and gender for US citizens whose intended graduate major was "physical sciences". The top and bottom of the lines are the 75th and 25th percentiles of the score distributions, respectively; the tick is the mean. This pattern is qualitatively unchanged when controlling for undergraduate GPA. Note the implications for diversity of using 700 as a minimum acceptable score: nearly three quarters of Hispanics would be rejected, and significantly more than this for American Indians, African Americans, and Puerto Ricans; similarly, women are filtered out at a higher rate than men. Mixing cut-off scores with these racial and gender disparities sets the foundation of a glass ceiling erected by the lopsided treatment of minorities and women before they even set foot in grad school.The author certainly presented some compelling statistics on why the GRE cutoff rule not only does not provide a good prediction on a student's performance in a graduate program, but also contributes to racial and gender disparities in admission.
And this brings me to another, slightly different item of discussion. The article looks at the diversity among the US students in physics. Many of us who went through the STEM educational program often see not only US students, but a large population of international students in these programs. In fact, in many schools, especially smaller ones, the number of international students can outnumber US students. This is definitely true in physics and engineering. There is a large population of international students from China, India, Korea, South America, etc.. So while there may not be as much "diversity" in the US student population in STEM fields, I find that there is a huge degree of diversity for the overall student population in these fields of study, more so then students in the liberal arts, economics, law, etc. Did you take an elective course in literature, art history, philosophy, etc.? How diverse in terms of racial/national origin were the students? How about those majoring in those fields?
Students in STEM areas have a larger opportunity to interact and experience students from other cultures and nationalities over a longer period of time. Often, they go through the degree program together. They tend to be more familiar in dealing with people from a wide variety of background. And you know what? If they continue work in such fields, the diversity carries over. Attend any physics or engineering conference, and you'll find a huge and significant international participation.
This diversity in STEM areas is often overlooked and is seldom considered as a strength in the development of students going through the program.