Why exam reports don't include 'raw data' or 'charts'

In the 70s, 80s and 90s, often a polygraph report to be used in court could include a tube of rolled up paper. It was a long chart paper of four wiggly lines with a lot of handwriting on it.

Modern-era polygraph testing is done using computerized equipment. No more ink and paper problems for examiners! The wiggly lines are instead viewed in colors as they move across a laptop screen.

The digital files involved are like movies in that they are harddrive memory-hogs. Many examiners discard them after reviewed for verbal results or for a written report. Regardless, these digital files can only be opened and viewed by persons who own the exact polygraph software used to do the original testing data capture, and there are four competing (and not at all interchangeable) polygraph software formats.

Typically, charts have no evidence value, as they are just wiggly lines with no provable indication of what was asked at that point in time, and there is no irrefutable proof as to when recorded or who was recorded. If 'the other side' doesn't believe an examiner's report, they won't believe charts either.

Also, some examiners guaranteeing privacy to their clients assure that all charts and notes involved in the testing are destroyed at the end of testing, and that no later discussion of the testing will be done without the examinee's permission.