When an IP anomaly is relatively complex, the application of such basic parameters as,ηs and Fs can hardly make reasonable interpretation of the nature of the anomaly source. With practical examples, the authors point out the effectiveness of applying the second information of IP, i.e., the metallic factor, to the interpretation of complex IP anomalies. The metallic factor can separate ore-related anomalies from barren ones, thus playing an effective role in the qualitative and quantitative appraisal of the anomaly.