There are several types of polygraph instruments on the market today. Each instrument records the same basic psychophysiological data as described above. The older instruments generated recordings using ink and paper but modern day technology uses a computerised system. Polygraph testing should not be confused with those who claim to detect lying using “voice stress analysis.” It is important to know that every independent scientific research project assessing the “voice stress” technology to date has found the test to be accurate between 47% and 52% of the time, which is little more than chance (flipping a coin). As such, the scientific community does not recognize “voice stress” as a reliable way to detect truth or deception.