  Two-jet event shape distributions, traditionally studied in the language of
perturbative QCD, can be described naturally in soft-collinear effective
theory. In this language, we demonstrate factorization of event shape
distributions into perturbatively-calculable hard and jet functions and
nonperturbative soft functions, and show how the latter contribute universal
shifts to the mean values of various event shape distributions. Violations of
universality in shifts of higher moments can give information on correlations
of energy flow in soft radiation.
