Indicator-concept links can run causally in either direction or not at all.

Evidence

One can ask about the relationship between the indicator and the concept: is it causal in nature? If so, what is the nature of this causal relationship? There are at least three possibilities worth exploring: (1) concept causes indicator, (2) indicator causes concept, and (3) a noncausal relationship. — Gary Goertz, Social Science Concepts, 374

Categorization

• DEFINE: Enumerates the three candidate logics — concept→indicator, indicator→concept, and noncausal — distinguishing correlational from causal measurement.