We measure what we find important.
Measures can and often become self-fulfilling targets. (read: Rankings and Reactivity by W. Espeland and M. Sauder https://www.stmarys-ca.edu/sites/default/files/attachments/files/rankings-and-reactivity-2007.pdf)
When a measure becomes a target it ceases to be a good measure.
So why measure?
Is observation and measurement part of a larger complex process which isn't finished until the process itself is finished?
This seems related to the measurement problem in quantum mechanics, Schrödinger's cat, the Heisenberg uncertainty principle, and the observer effect).