Concept structures can differ across levels, but some combinations are rare.

Evidence

In the basic framework one can use different concept structures for different levels, e.g., best shot at the data–indicator level and weakest link at the secondary level, or the mean at both levels. In practice, some combinations appear particularly popular or make more sense than others. For example, best shot at the secondary level with weakest link at the data–indicator level is rare for concepts (chapter 10 briefly discusses causal models with this structure which are standard in QCA). — Gary Goertz, Social Science Concepts and Measurement, 1030

Categorization

• DEFINE: Clarifies that the ‘basic framework’ allows per-level aggregation choices, a technical distinction worth pinning.