A theoretical basis for defining and measuring the quality of institutions of higher education, namely for accreditation purposes, is developed. The theory, the Attributive Theory of Quality, is illustrated using a calculation model that is based on general systems theory. The theory postulates that quality only exists in relation to the phenomenon to which it is attributed. Quality can be defined by its attributes and can be quantified by developing a system of numeric values for the attributes. An intersubjective approach to data collection and analysis requiring participation by experts is recommended. To illustrate how the theory can be operationalized, a model was developed using Lotus 1-2-3 and tested with data from an evaluation of five community college libraries. Results were verified against similar data from a panel of five library experts. The study illustrates the reliability of the method. Further research to test the model is recommended. A 154-item list of references is included. Two tables present data from the illustrative study. (SLD)