  We describe a classical model that may serve as an analog for joint and local
measurements of an entanglement witness. The analogous experimental procedure
and data analysis protocol of the model follow those of a previous experiment
to measure an entanglement witness with polarized photons prepared in a mixed
state [Phys. Rev. Lett. \textbf{91}, 227901 (2003)]. Numerical simulations show
excellent agreement with both experimental results and quantum-mechanical
predictions. This agreement is made possible by the fact that the model
exhibits contextuality due to the postselection of coincident detection events.
