Science, or Blinded By Science ?
 
For a a DOD technology to claim it is science, the process should be verifiable and produce identical
results time and again. There is simply no way that in field testing, that an examiner or examiners will produce the identical score on same subject, on same day, for same issue, using same questions.
Not to a claimed level of 98%. Not now, not ever. Hell, most of them cant even make the same final call.

Insofar as polygraph is concerned, there are just too many subject behaviours that can and do occur - all of which render the affected question unscorable. If there are artefacts present, the tracing should not be scored. There is no middle ground. 

When an examiner has to tell the subject to sit still, dont swallow, dont cough, breathe normally (!?)
dont turn your head, look straight, dont look around the room, etc etc - then the examination has become artificial and farcical. What does a subject do when told to breathe normally? He regulates his breathing to comply. Can he regulate it all the time to the same degree? No.
A 30 second tracing without artefacts is a rare animal.

When examiners resort to card tricks and the hidden number trick, then, my dear fellows, we are practising our own brand of BS and subterfuge, smoke and mirrors.

VSA utilises spectography ( a proven science) and a stable algorithm to produce a scorable tracing.
But is the tracing actually scorable? No. Not in the true sense. Scoring VSA tracings is an art. Sometimes
your artwork is good and sometimes not so good.

Both are inert technologies. They are not possessed of artificial intelligence. So to answer the universal
question: Which is more accurate? The answer is 'Neither'. Accuracy is vested solely in the examiner.
Unfortunately, skill only comes with experience - which means that a lot of people are tested by poorly
skilled examiners. Then again, some examiners are bums for their entire DOD careers. Scary.

Many years ago I began to utilise Statement Analysis as my prime investigative tool. It is powerful
and scientific. Many might not know that SA was mandated into the German legal system back in
the early 50's. Deceptive subjects are caught out with their own words and not with smoke & mirrors.

Unfortunately, making a DI call on a subject based purely on SA produces argument between subject and examiner as the examination then becomes a personal confrontation. So, when using SA it is advisable to hide behind a polygraph or cvsa.

Granted, both polygraph and vsa examiners get confessions, but so does a colander on the head
wired to a Xerox machine. 

I have 15 yrs Polygraph and VSA experience at Examiner and Instructor level plus 9 yrs experience combined with ongoing research into Statement Analysis in its various formats.