A: Mechanical (or analog) polygraph equipment has been around for 50 years and is still widely used today. Just a few years ago computerized polygraphs were developed. These new systems included complicated chart analysis formulas and inkless display systems (on a computer screen rather than a roll of chart paper). Scoring of the charts is done the same for both systems, but the computerized system has built-in aids for the examiner and prevents equipment failures that are sometimes experienced with mechanical equipment. In our opinion, at this time the computerized systems are not well-enough advanced to be called superior to the analog systems, although they are admittedly easier to use. A competent and qualified examiner can be equally effective with either system.