Studying the dynamic nature of commitment – that is: the process of committing – requires a fitting temporal process mindset. This involves thoughts and ideas on how phenomena change, grow, vary, and terminate over time. If we truly want to come to grips with the role of time and change, however, we also need to set up our studies in such a way that theory and research design are aligned with our measurement practices. The study of temporal process research comes with a new set of principles and measurement criteria that are not in line with conventional ‘differential’ thinking. Measuring commitment as a ‘timeless’ trait is fundamentally different from measuring it as an evolving process. The authors specify five critical areas of difference and forward new design features for an instrument to properly measure the committing process. Many of these features contrast starkly with those of conventional cross-sectional commitment research instruments.