McFadden Pseudo R-Squared
The McFadden pseudo R2 compares the log likelihood of the full model (L) to the log likelihood of the model with just the intercept (L0, the null model).
R2=1.0−ln(L)ln(L0).
References
D. McFadden. Conditional logit analysis of qualitative choice behavior. In P. Zarembka, editor, Frontiers in Econometrics, chapter Four, pages 104–142. Academic Press, New York, 1974.