With the introduction of the zone comparison test by Backster in 1960, a new type of question emerged known as the symptomatic. Backster theorized that when subjects did not physiologically react to relevant or control questions, they were anticipating some question about an outside issue that dampened their response to questions that would ordinarily be a stimulus. Backster further reasoned that by the inclusion of questions at specified points in the examination, the examiner could identify the presence of the outside issue and then resolve it. Backster believed this technique would reduce inconclusive diagnoses in control- question tests by as much as two-thirds. To test Backster's hypothesis, this study requested three experienced examiners to conduct every other examination without the symptomatic questions usually included in the zone comparison format. Irrelevant questions were inserted in place of symptomatic questions. A total of 150 zone comparison polygraph examinations were conducted by the examiners. Results confirmed Backster's prediction that the use of symptomatic questions would reduce inconclusive diagnoses by two-thirds. Suggestions for additional research are offered. 3 tables, 20 references, and data sheets