I thought irrelevants weren't scored?

Research conducted by Frank S. Horvath and John E. Reid (1972) revealed that the Silent Answer Test produces better respiratory patterns by eliminating causes of distortions from the examinee who prepares himself or herself to answer each question aloud by inhaling a great amount of air; from the examinee who loudly bellows his or her answer to emphasize his or her denial; from the examinee who feels compelled to give an elaborate answer instead of a simple "yes" or "no" as instructed; and from the examinee whose throat is dry or irritated necessitating the clearing of his or her throat or coughing at intervals during the test.

Their research further indicated an enhancement of the utility of the electrodermal (GSR) recording. The SAT not only produced a chart with greater purity of tracing but also acted as an effective stimulation test for the subsequent polygraph tests/charts requiring a verbal answer.

The stimulating effect of the silent answer test on the guilty examinee may be due to the dilemma encountered when told he or she is not to answer the questions aloud but truthfully and silently to himself or herself. Previously the examinee has geared his or her defenses so that his or verbal answer to the relevant questions would not betray him or her. Now the examinee wonders whether he or she should answer those questions truthfully to himself or herself and presumably not show a reaction, which may reflect a different pattern than the previous charts, or silently answer them the same way as before and perhaps show a strong reaction as he or she may have on previous charts. This causes an inner conflict, a feeling of helplessness, which carries over into the subsequent test requiring a verbal response. The guilty examinee must now readjust his or her defenses again in preparation for his or her verbal responses to the relevant questions, which causes his or mind to race inasmuch as the two tests are administered back-to-back. The examinee's concern is on the relevant questions, which are now an even greater threat to his or her well-being which increases the strength of his or her psychological set onto the relevant questions and creates greater and clearer responses. The Silent Answer Test has the effect of enhancing the threatening power of the relevant questions to the guilty examinee, and conversely also enhances the innocent examinee's concern over the probable-lie control questions inasmuch as the relevant questions should be of no concern to him or her.

While most polygraph techniques employ the Silent Answer Test as a stimulation test and/or countercountermeasure, usually after the second chart, some polygraph techniques use the SAT as the very first test prior to the administration of the relevant issue test and include the SAT data in their decision-making process.