It is suggested that a certain visuo-spatial task may provide a useful measure of the severity of dysfunction in schizophrenia. Accordingly, a comparison is made between the scores gained by a group of schizophrenic patients on this task, and the more usual measure - a nurse rating the patients as of considerable dysfunction or moderate dysfunction. So that the scores in the visuo-spatial task will be comparable the patients are classified as taking either a long time (10 or more minutes) to complete the task, or taking a short time (less than 10 minutes).