Summary. A theory is developed to measure the quality of applicants into UK higher education. It is based on the principle that more able applicants will self-select into more difficult subject choices. The advantage is that it gives a unidimensional measure whereby different groups can easily be compared across any dimension of interest, e.g. men, women and the various ethnic groups. Here the relative quality of applicants and acceptances across 170 separate subject groups is calculated and discussed by using a data set with over 2 million observations. It, therefore, offers a way of achieving a more refined measure of the quality of human capital.