The Mule,

Only you can make the decision on whether or not to tell the truth on the "test." Nonetheless, you should know that CVSA is a complete fraud that has never been shown to determine truth from deception in any study (peer reviewed or otherwise) except those done by the company making the device!  

At this time, we know of no way to manipulate CVSA results to ensure a passing outcome.  The best I can tell you is that an examiner friend of mine has told me that answering the questions with an “I don’t give a shit” (his words) attitude seems to increase the chances of passing (keep in mind that this is nothing more than anecdotal evidence).  On the positive side, many users of this device know that it is flawed.    Although the maker of the device claims 90%+ accuracy rates, they write in the examiner's manual that CVSA should never be used as a sole determining factor in making employment decisions. If you are rejected for a job because of a CVSA test alone, it appears you would have good grounds for a lawsuit against the employer. 

The primary value of the device is as an interrogation prop.  The most important thing to remember is to decide what you plan to admit BEFORE setting foot into the examiner's office (only you can make this decision). Once you show up for the test, MAKE NO DAMAGING ADMISSIONS PAST WHAT YOU HAVE ALREADY PROVIDED IN THE BACKGROUND FORMS, NO MATTER WHAT THE EXAMINER TELLS YOU.  The examiner is likely to attempt to get you to change your statements, etc.  If you told the department that you used marijuana five times, when the examiner asks, the answer is five, exactly five, and you are 100% sure that the number is correct. Remember, the examiner is a seasoned interrogator. He will likely first try to get you to admit that you are not 100% sure that you number is correct and then prod you into recanting.  Once you do, you are toast.  Do not fall for it!

You should make yourself familiar with common interrogation tactics and learn about the behavior that interrogators (including polygraphers and CVSA jockeys) associate with deception.  Unfortunately, it seems that nearly everything you do can be considered indicative of deception. Nonetheless, be on time (the CVSA manual actually tells the examiner to adjust your score negatively if you are late).  Dress professionally.  Maintain eye contact.  Attempt to establish a friendly yet professional rapport with the examiner (just don’t overdo it). Avoid touching your face, scratching your nose, etc when answering questions. Make general denials (I have never used any illegal drugs) as opposed to specific ones (I have never even smoked marijuana). 

More information on interrogation can be found in the Department of Defense Polygraph Examiner's Interrogation Handbook (available in the AntiPolygraph.org Reading Room).  Furthermore, the next edition of The Lie Behind the Lie Detector (which will be available by the end of the year)will feature much more of this information.

Lastly, remember that no matter how friendly the examiner may seem, his job is to get you to make damaging admissions. Law enforcement agencies almost always select their most skilled interrogators for CVSA training. The worst thing you can do is to buy into the act that the examiner is attempting—namely that he is a super nice guy just there to help you get on to the next step of the process, etc. While the examiner may indeed be a nice guy outside of the testing room, his CVSA training includes instruction on how to project a false sense of empathy for your situation. DON’T buy it.  The most common mistake made by those who make damaging admissions is to buy into the act that they somehow got the one examiner who is somehow different from all the others and is out to help the examinee instead of gather admissions. While I would be on careful guard when submitting to any type of lie detection interrogation, I would be at my most heightened state of alert when facing an examiner who uses this approach (as opposed to one who uses screaming, cursing, etc). The most skilled interrogators often realize that you can catch more flies with honey than vinegar. So beware!