Your school has improved, so why is it stuck in the same spot? An engineer explains.
When U.S. News & World Report issues its latest graduate-school rankings this month, people across the country will scratch their heads. Why, they will ask, do so many schools remain at the same rank even though academics struggle—and donors spend lavishly—to improve their universities’ stature?
In fact, there’s an engineering answer to this puzzle, though not one that will cheer fundraisers. It’s called Constructal Theory, and it shows that the hierarchy of universities will stay quite rigid despite improvements at individual schools.
Constructal Theory holds that all currents adjust to a configuration that lets them flow more easily, generating a specific design—or drawing. The spread of knowledge and the reputations of professors and universities are among such currents.
To illustrate how the theory works, let’s use the Amazon River basin as an example. Water from the Amazon plain flows from tributaries that, together with the river itself, form a tree-shaped pattern. This pattern of wide and narrow waterways provides the best possible arrangement of routes for the water to flow from the plain to the mouth of the Amazon. A natural hierarchy forms according to the amount each waterway carries.
A simple-minded designer might be tempted to change this system and direct each droplet of water in a straight line. But the result would not be as efficient as the natural design that has evolved over time.
This tendency to go with the flow and thereby generate a design is repeated not just in river basins around the world but throughout nature and society. It is the fabric of vascularization in inanimate systems, such as lightning, and animate systems, such as circulation, the nervous system, and the lungs. It can also be seen in the development of such urban systems as traffic, water, and electricity. The natural phenomenon of “design generation” unites all these fields and makes design a part of science.
Here’s how the theory applies to university rankings:
Like the water of a river basin, education flows across the globe. A university becomes visible through the ideas generated by its faculty and researchers. A good measure of visibility is the number of citations of an author’s creative work, as compiled in a list of the most cited authors (www.isihighlycited.com). When many people use an author’s work, the idea flows from one to many. It flows “well” because of the long history and entrenched geography of the flow network, which is the result of the evolutionary process that brought the sharing of knowledge among people and institutions to its present level of effectiveness.
Count the number of highly cited authors for each university, and you will discover a convincingly strong relationship: Highly ranked schools have many names on most-cited lists, while the lowly ranked have comparatively few. The result is that universities and other institutions form a hierarchical network of channels, which provide maximum access for the global flow system. The highly ranked and lowly ranked find their natural spaces within the network.
Attempts to change this design artificially are unlikely to produce a system that is as robust or as perfect in the dissemination of knowledge. Nor will they have much effect on the hierarchy of institutions.
As one school strives to excel, investing in faculty or research, so will others. Education improves over time because each school becomes more productive of ideas. Yet because the overall flow of knowledge increases, each school retains its relative level of visibility. Every student who enters a university has a view of which universities are better, because the better ones are more visible. The better students and professors will flow to the most visible schools because both want to secure the best possible position in society.
Thus, the evolution of the flow of education is like a river basin or delta during the rainy season: All of the streams swell, but the size of each, when compared with others, stays the same.
There you have it: Schools may get better, but their rankings won’t change.
Adrian Bejan is J. A. Jones Distinguished Professor of Mechanical Engineering at Duke University. His most recent book (with G. W. Merkx) is Constructal Theory of Social Dynamics (www.constructal.org).