A data signal processing device includes a load calculator and a compensation processor. The load calculator calculates an on-pixel rate (OPR) based on image data signals and positional weight values. The positional weight values are determined based on locations of pixels in a display panel. The OPR is proportional to a frame luminance load, which corresponds to a sum of driving currents for the pixels to emit light in each of a plurality of frames. The compensation processor compensates distorted luminance caused by the frame luminance load based on the OPR.