  An important aspect of astrophysical MHD turbulence research is developing
diagnostics to connect simulations with the observable universe. Turbulent
systems are by definition structurally complex in all fluid variables (density,
velocity, and magnetic field), such that they must be described statistically.
By developing and applying diagnostic tools to simulation data, it is possible
to interpret empirical laws for the statistical properties of observed systems
in terms of fundamental dynamical processes, and to identify and calibrate
robust probes of physical parameters that cannot be measured directly. Using
several different examples, I describe how structural diagnostic analyses have
already yielded significant insights into the nature of turbulent molecular
clouds. I review results from several different groups, and discuss directions
for future diagnostics to enhance our understanding of cloud structure and
constrain models of the evolutionary course that governs star formation.
