What Do the Ranges Mean?
If you’re the sort of person who favors a simple imperative weather forecast (“Take the umbrella!”), then you may also long for a graduate-school ranking system that just tells you which program to pick. Unfortunately, the information gathered by the NRC will not support such an unequivocal declaration. There’s no choice but to cope with uncertainty. Given a set of rankings—or, rather, ranges of rankings—like those shown below, which program should you prefer? It’s easy to see that programs A and B are considered superior to programs G, H and I, since there is no overlap in their rankings. But making finer distinctions can be tricky. Is program B better than C? The graph shows that C’s range of rankings extends down to fifth place, whereas B cannot be lower than fourth place. Thus there’s a tendency to assume that B must be better. Nevertheless, it is entirely consistent with the data that the “true” ranking—if only we could know it—would put C in the No. 1 spot and B in fourth place.
