This paper describes the Short Dementia Questionnaire (SDQ), a psychometric test that provides an initial assessment of the severity of cognitive impairment in patients with dementia. This test requires minimal effort on the part of the assessor and places little strain on the patient. For several years now, a preliminary form of the test has been used for large-scale screening of dementia patients in nursing homes within clinical drug trials. This test is short, inexpensive and largely standardized in regard to implementation, even without the usual intensive training. This paper focuses in particular on the structure and implementation of the test. The item and scale parameters relevant for the evaluation of its field of application are presented, and finally, the results of an initial validation study are reported. These results show that the test procedure is a good predictor of severity scores in frequently used, more extensive tests for grading the severity of dementia. (c) 2001 Prous Science. All rights reserved.