  The $\Delta_3(L)$ statistic of Random Matrix Theory is defined as the average
of a set of random numbers $\{\delta\}$, derived from a spectrum. The
distribution $p(\delta)$ of these random numbers is used as the basis of a
maximum likelihood method to gauge the fraction $x$ of levels missed in an
experimental spectrum. The method is tested on an ensemble of depleted spectra
from the gaussian orthogonal ensemble (GOE), and accurately returned the
correct fraction of missed levels. Neutron resonance data and acoustic spectra
of an aluminum block were analyzed. All results were compared with an analysis
based on an established expression for $\Delta_3(L)$ for a depleted GOE
spectrum. The effects of intruder levels is examined, and seen to be very
similar to that of missed levels. Shell model spectra were seen to give the
same $p(\delta)$ as the GOE.
