This brief report presents the frequency distributions for the most common equivalent linear range geomagnetic activity indices. We believe that these distributions are useful indicators of certain kinds of artifical components in the information content of the indices. The 3-hour aa index is shown to have a particularly strong artifical compenent, as evidenced by its highly irregular frequency distribution. We point out that additional averaging of the indices, as in the derviation of half-day or entire-day indices, results in a more regular distribution. Thus we argue that the regular character of the distribution of the ap index is probably largely a result of the more extensive averaging used in the derivation of this index and that ap may still contain a substantial, but masked, artifical component. The process by which the equivalent linear range indices are derived from the strongly quantized intermediate K indices is identified as the most prominent source of such artifical contamination, and we suggest that improved indices might be obtained by deriving them directly from the actual geomagnetic component data.