retcopper wrote on Feb 23^rd, 2006 at 6:25pm:

Renraw P.S. Contrary to what Polyfool writes, an inconclusive  call is rendered  because your physiological responses to certain questions were not able to assist the examiner in calling the chart deceptive or truthful.

True. However, when an INC is rendered, it is considered in the polygraph community, to be an error on the part of the examiner. For example, the examiner didn't spend enough time preparing the examinee during the pre-test or failed to get the examinee to hold back on the control questions. That would explain the reasoning behind the examinee being offered a follow-up polygraph--something went wrong through no fault of the examinee.  

I don't necessarily agree with this arguement because the test is so utterly flawed, there are so many things that can and will go wrong.