Cognitive interviews play an important role in articulating the intended construct of educational assessments. This paper describes the iterative development of protocols for cognitive interviews with kindergarten through second-grade children to understand how their spatial reasoning skill development aligns with intended constructs. We describe the procedures used to gather evidence of construct relevance and improved alignment to task-based interview items through multiple pilot rounds before conducting cognitive interviews. We found improved alignment and reduced construct irrelevant variance after protocol revisions.