Exact, reproducible and well maintained international standards are needed not only in the natural sciences and engineering, but are of increasing concern today in education, health care, government, business intelligence, and the economy at large. Metrological practice gives rise to complex adaptive systems in which meaningful relationships are socially conceived and brought to life. All scientific units should be established with equal rigor, and all measures should be based on consensus standard metrics valued for their accuracy, stability and availability. Fifty years of research and practice employing probabilistic models of psychosocial constructs document individual-level structural invariances capable of supporting metrological traceability. Complex adaptive systems of this kind offer new opportunities for extending the true union of mathematics and measurement into the psychosocial sciences