That which is not derived exclusively from the polygraph waveforms or tracings. Some polygraph schools teach that there are sources of information to assist the polygraph examiner in rendering a decision that are not registered in the physiological data. These sources of extrapolygraphic information include case facts, behavioral indicators, and base rates. Blind interpretation of polygraph charts is one way of parsing out what information is available in the test recordings and that which comes from other sources.
