Depending on different load characteristics, various power quality disturbances such as sag-swell, harmonics, inter-harmonics, and flicker, appear in electric power systems. Among these power quality disturbances, the flicker is one of the critical power quality phenomenon due to the lack of source detection and disturbance responsibility sharing method. The measurement of the flicker level is defined in the IEC 61000-4-15 standard by a flicker meter. This meter deals only with voltage signals and is not sufficient to understand the contribution of the load and background power systems separately. Thus, this paper proposes new approaches to the evaluation of flicker characteristics using the real on-site measurements taken from two different iron and steel factories. The novelty of this paper is investigating the flicker characteristics in light of statistical methods, spectral and multi-resolution wavelet analysis, and the information theory based wavelet energy entropy analysis together, and proposing a new index to interpret the flicker responsibility of load and power system. This proposed index is called Flicker Contribution Ratio (FCR) and represents the percentage flicker disturbance responsibility of both load and power system.