<p>Yale (like any other top school) needs to balance out the student body so that at any given time there are the “desired” number of undergraduates who are majoring in every department. This is simply a matter of balancing out supply and demand. And I’m not talking about intro level classes that are needed to fulfill distributional or pre-med requirements- I’m talking about more advanced classes and research opportunities that will only be attractive to students who want to major in the field.</p>
<p>The Biology department has no shortage of students signing up for their advanced classes, or wanting to do research projects in their lab. Much of this is driven by pre-meds who want to position themselves for medical school, whether they are interested in research or not.</p>
<p>The other Science and Engineering departments at Yale do have a problem with low demand. It is only natural- Yale has a pre-eminent reputation in the humanities and social sciences, and a pretty strong reputation in the biological sciences, but it really cannot compete against a place like MIT in Engineering or Physics. If Yale did not make extra special efforts to recruit students in these areas, there would be too few students majoring in these disciplines and that would in the long run prevent these departments from growing and getting better. This is the reason Yale makes a special effort in this area- to break the vicious cycle of weak departments attracting fewer and weaker students leading to further weakening of departments.</p>
<p>Another point- you really can’t use the raw numbers of students to estimate whether a department has a shortage in a given area. Every department can ‘handle’ only a certain number of students and this varies tremendously. So if the English department suddenly had 30 majors per year that would be a huge shortage while the classics department would probably be overloaded if it had 10 majors in a year.</p>