  In quantum nanoelectronics, numerical simulations have become an ubiquitous
tool. Yet the comparison with experiments is often done at a qualitative level
or restricted to a single device with a handful of fitting parameters. In this
work, we assess the predictive power of these simulations by comparing the
results of a single model with a large experimental data set of 110 devices
with 48 different geometries. The devices are quantum point contacts of various
shapes and sizes made with electrostatic gates deposited on top of a high
mobility GaAs/GaAlAs two dimensional electron gas. We study the pinch-off
voltages applied on the gates to deplete the two-dimensional electron gas in
various spatial positions. We argue that the pinch-off voltages are a very
robust signature of the charge distribution in the device. The large
experimental data set allows us to critically review the modeling and arrive at
a robust one-parameter model that can be calibrated in situ, a crucial step for
making predictive simulations.
