Advances in methods for longitudinal data collection and analysis have prompted a surge of research on psychological processes. However, decisions about how to time assessments are often not explicitly tethered to theories about psychological processes but are instead justified on methodological (e.g., power) or practical (e.g., feasibility) grounds. In many cases, methodological decisions are not explicitly justified at all. The disconnect between theories about processes and the timing of assessments in longitudinal research has contributed to misspecified models, interpretive errors, mixed findings, and nonspecific conclusions. In this article, we argue that higher demands should be placed on researchers to connect theories to methods in longitudinal research. We review instances of this disconnect and offer potential solutions as they pertain to four general questions for longitudinal researchers: how time should be scaled, how many assessments are needed, how frequently assessments should occur, and when assessments should happen.

纵向数据收集和分析方法的进步促进了对心理过程的研究。然而，关于如何进行时间评估的决定通常不会明确地与心理过程的理论联系在一起，而是基于方法论（例如，权力）或实践（例如，可行性）的理由来证明是合理的。在许多情况下，方法决策根本没有明确的理由。纵向研究中关于过程的理论和评估时间之间的脱节导致了错误指定的模型、解释错误、混合的发现和非特定的结论。在本文中，我们认为应该对研究人员提出更高的要求，以将纵向研究中的理论与方法联系起来。