Existing methods for handling patients’ opinions as a basis for quality improvement measures tend to be too sophisticated for practical nursing and/or weak psychometrically. An Index of Measures was developed by combining patients’ perceptions of actual care conditions with the subjective importance they ascribed to these conditions. Data from Swedish somatic inpatients (n = 4002) indicated that this index gave added value compared to patients’ ratings of actual care conditions only. Interpretation of the Index of Measures focused on the proportion of patients who receive the value ‘deficiency.’ This value is obtained if a given patient has a subjective importance rating on a given item which is higher than the mean subjective importance score for the whole patient group on that item, as well as a perceived reality rating on the item in question which is lower than the mean perceived reality rating for the whole group on that item. Guidelines are suggested on when improvement actions are necessary and when they are not necessary.