Beyond analyzing the methods and categories individually, it is also possible to investigate which study methods co-occur within the NTS reports, thereby uncovering meaningful relationships between them. The following plots illustrate how different research components — such as Experimental Paradigms / Frameworks, Manipulations / Procedures, Tests / Apparatus, and Data Acquisition Methods — are related across the NTS data. Each Sankey diagram visualizes the flow and connections between these categories, revealing patterns of methodological co-occurrence.