A different approach to university rankings
Educationalists are well able to find fault with rankings on numerous grounds and may reject them outright. However, given that they are here to stay, we could also try to improve them wherever possible. All currently published university rankings combine various measures to produce an overall score using an additive approach. The individual measures are first normalized to make the figures 'comparable' before they are combined. Various normalization procedures exist but, unfortunately, they lead to different results when applied to the same data: hence the compiler's choice of normalization actually affects the order in which universities are ranked. Other difficulties associated with the additive approach include differing treatments of the student to staff ratio, and unexpected rank reversals associated with the removal or inclusion of institutions. We show that a multiplicative approach to aggregation overcomes all of these difficulties. It also provides a transparent interpretation for the weights. The proposed approach is very general and can be applied to many other types of ranking problem.