The technique for calculating quality indices (QI) and stability indices (SI) of an information security model consists of two successive stages. The quality index of the enterprise information security model under study (QI) equals: QI = ?P1i / ?Pi (i=n), while the stability index (SI) is equal to: SI = ?Pi (i=n) / ?P2i, whereP1i, P2i–partial indices of indicators of interests of,respectively, enterprise quality and stability; Pi–quantitative values of the standard; i = 1,2, ...; n–number of indicators and preferences in the scale. Having at hand the values of the QI and SI, an efficiency index EI for the enterprise information security model is calculated next as an arithmetic mean value of the obtained indices – QI and SI, whichonce again underlines equality of the categories “quality” and “stability” in societal life: EI = (QI + SI) / 2.