A simple question for many, idle for others, but necessary to answer for everyone, is why the comparison question occupies a first position based on the relevant question when it comes to format sequences corresponding to deception polygraph techniques. This questioning is transcendent when it occurs in the context of the scientific, legal debate, or due to the scrutiny of polygraph consumers who make administrative decisions based on the diagnostic results. However, within the polygraphy union it seems that the answer has been dealt with in informal settings, in hallway talks or as a classroom topic, but the truth is that its documentary formality seems to be scarce, for this reason, this discussion has the intention of providing basic knowledge to field examiners about this procedural unknown, of which, we are convinced that they are the ones who must be prepared to answer this and other procedural questions in order to maintain the scientific reputation of our profession.