  We present preliminary data fit results of synthetic light curves computed
from numerical afterglow blast wave simulations. Our technique uses Markov
chain Monte Carlo (MCMC) in a new data analysis tool, ScaleFit. Scaling
relations in both the hydrodynamics and radiation equations allow light curves
to be parameterized by a small set of scale-invariant characteristic
quantities. These quantities have been calculated and tabulated from high
resolution two-dimensional hydrodynamic simulations. Producing a light curve
from the characteristics takes only a millisecond, allowing for the use of MCMC
data fitting techniques which can require millions of iterations. ScaleFit is a
portable, lightweight, python package which performs this analysis on afterglow
light curves. Using the set of Swift-XRT light curves from 2011 & 2012 with
known redshifts, we find ScaleFit can measure the jet opening angle, observer
angle, and spectral index of most afterglows. Globally we find gamma-ray burst
afterglows tend to be observed off axis, at a significant fraction of the jet
opening angle.
