The primary function of premedication today is to allay anxiety. Thus the methods used clinically to assess premedicant drugs should be capable of measuring the degree of sedation produced. Subjective assessment alone is liable to error and difficult to quantify. Objective signs of anxiety and sleep have been described and used by others to measure these subjective responses. Some of this work is reviewed. The possible use of a scoring system based on objective signs is examined and the difficulties which result from the inclusion of many variables are indicated, and ways in which they may be minimized are discussed. Some problems of statistical analysis of data obtained in this way are discussed.