The use of multiple description (MD) video coding and path diversity has been proposed to provide improved performance over lossy packet networks [1]. The goal of this work was to develop models to accurately and quickly predict and compare the distortion of MD video coding and path diversity against conventional single description (SD) video delivered over a single path. In the process, we developed (1) a model for the loss process of a two-path path diversity system, and (2) a distortion model that maps the loss model to MD distortion values. Given these models we present a number of comparisons between MD video coding and path diversity and conventional SD video over a single path. The proposed model for path diversity may also be useful in other applications not related to MD coding. Furthermore, other forms of MD coding may be analyzed using similar models for MD distortion. 4 Pages