Measuring Public Service Motivation: Exploring the Equivalence of Existing Global Measures

Our ability to interpret, generalize, and build theory across public service motivation (PSM) studies is limited by lack of knowledge regarding the equivalence of different PSM measures that researchers frequently use. While past research has given considerable attention to validating multidimensional measures of PSM, this study investigates the psychometric properties of the global measures that have been used to provide much of the empirical evidence on PSM. Building on the lessons of other research using global and multidimensional measures, we first discuss the strengths and weaknesses of existing global measures of PSM relative to those of the multidimensional measures. After highlighting the potential merit of global scales, we then provide empirical justification for global scales. Using five different data sets to compare commonly used global measures of PSM, our findings suggest that these different measures are not only highly correlated with each other but also display a similar pattern and strength of relationships with important correlates of PSM. These findings suggest that these measures do tap into the same conceptual space and help validate our continued reliance on empirical studies that have used different measures to build our understanding of PSM.