CVSA III is showing clipped patterns

[James Kane]

As a polygrapher and voice stress examiner, I have noticed what I believe is a flaw in the CVSA III, which is the voice stress analyzer that NITV is currently selling.

My department purchased a CVSA III about two years ago and uses it in our pre-employment screening process.

I have noticed that the voice stress patterns displayed by our unit don't have precursors or post-cursors. Discussing this observation with other voice stress examiners, some with other departments and some who were certified years ago, identified that voice patterns must have both precursors and post-cursors to be correctly evaluated. According to my training and these other voice stress examiners, the precursors and post-cursors assist with evaluation, ensuring none of the patterns are clipped. I remember from my training that a clipped non-stressful pattern can be misinterpreted as a stressful one, thus the need for the precursor and post-cursor.

I have looked through our CVSA III manual, and the patterns depicted in it show patterns with both precursors and post-cursors, yet our department's CVSA displays patterns with no precursors and post-cursors.

From our CVSA III manual, page 33: See Attachment 1

Most of the patterns in the manual show a precursor and a post-cursor, as depicted in the above-referenced attachment. The GREEN circles in the graphic further identify these patterns.

The following patterns are from our actual CVSA III: See attachment 2

The above-referenced patterns are missing precursors and post-cursors, as depicted by the RED circles in the attached graphic.

From what I understand, the standards for the voice stress industry require patterns to have both precursors and post-cursors to be correctly evaluated.

Is anyone else with a CVSA III having the same issues?

[Anthony R]

There is a defect in all CVSAs, polygraphs, etc.  None of them work—just a pseudo-science dog and pony show.