<p style="text-align: left;"><span style="">A quantitative database should represent the mix of ages, gender, ethnicity, socioeconomic status and other demographic factors present in the overall population. The method of recruitment of normal individuals also should be considered. Poor screening procedures will result in admitting individuals into a normal group who have signiﬁcant clinical problems. Regardless the method of recruitment, care must be exercised not to entice individuals to participate and falsify information because of the ﬁnancial gain. Normative databases are to be constructed and validated in respect to the basic scientific standards of gaussianity, cross-validation, amplifier matching and peer reviewed publications.<br></span></p>