Leadership has been studied using quantitative, qualitative, and mixed methods (a combination of quantitative and qualitative) research methodologies. From a quantitative psychology orientation, statistical and mathematical modeling has been used in the development of leadership scales, in testing established leader evaluation tools, and in examining perceptions of leaders.[23] Quantitative analysis may also take an experimental approach, incorporating methods from the field of experimental economics.[24] Survey methodology has also been widely used in leadership research.