A physical analysis is presented of the Starr, Nickerson, and Dock methods for registering the ballistocardiogram. It is shown that many forms of distortion are present. Some of the distortion may be present in the instrumentation which may be controlled, and other forms of distortion are inherent in the subject under test which are most difficult to control or evaluate. The effects which some of the uncontrollable variables have upon the amplitudes and temporal positioning of the registered ballistocardiographic waves is analyzed. The status of static and dynamic standardization procedures is discussed. A "Glossary of Technical Terms" is appended.