Discovering improved electrocatalysts is critical for many technologically important processes and for the development of new clean-energy technologies. High-throughput methods for measuring fundamental electrochemical properties are demonstrated through the investigation of oxygen-evolution catalysis by using 665 oxide compositions containing nickel, iron, cobalt, and cerium. The behavior of each composition is characterized in 1.0 M NaOH(aq) by using a scanning drop three-electrode cell to perform chronopotentiometry (CP) and cyclic voltammetry experiments. CP measurements at different current densities identify different composition–performance trends, owing to underlying variations in fundamental electrochemical behavior. We report systematic, coincident, composition-dependent trends in the Tafel slopes and the reversible redox potentials of the catalysts. Applying high-throughput electrochemical methods provides insight into composition–property–performance relationships and motivates new directions for the study of catalyst mechanisms by using informatics and theory.