  We establish an observation inequality for the Schr\"odinger equation on
$\mathbf{R}^d$, uniform in the Planck constant $\hbar\in[0,1]$. The proof is
based on the pseudometric introduced in [F. Golse, T. Paul, Arch. Rational
Mech. Anal. 223 (2017), 57-94]. This inequality involves only effective
constants which are computed explicitly in their dependence in $\hbar$ and all
parameters involved.
