  Time-Delay Cosmography is a technique for measuring $H_0$ with strong
gravitational lensing. It requires a correction for line of sight
perturbations, and it is necessary to build tools to assess populations of
these lines of sight efficiently. We aim demonstrate the techniques necessary
to analyze line of sight effects at a population level, and investigate whether
strong lenses fall in preferably overdense environments. We analyze a set of 25
galaxy-galaxy lens lines of sight in the Strong Lensing Legacy Survey sample
using standard techniques, then perform a hierarchical analysis to constrain
the population-level parameters. We introduce a new statistical model for these
posteriors that may provide insight into the underlying physics of the system.
We find the median value of $\kappa_{\rm{ext}}$ in the population model to be
$0.033 \pm 0.010$. The median value of $\kappa_{\rm{ext}}$ for the individual
lens posteriors is $0.008 \pm 0.015$. Both approaches demostrate that our
systems are drawn from an overdense sample. The different results from these
two approaches show the importance of population models that do not multiply
the effect of our priors.
