The System Coherence Index (SCI): A General Methodology and Framework for Measuring Alignment Under Constraint

The System Coherence Index (SCI) is a value-neutral, scale-invariant methodology designed to detect directional alignment in complex systems under stress. Rather than measuring performance, welfare, or optimality, SCI identifies whether subsystems respond to pressure in a coordinated or fragmented manner. This paper formalizes SCI as a general research framework applicable across structural, social, organizational, and individual domains. It defines indicator selection rules, directional assignment criteria, study design protocols, aggregation logic, and interpretive limits, enabling independent replication and domain-specific studies. Prior empirical applications of SCI are referenced; this paper focuses exclusively on methodological foundations.