Binder parameter

The Binder parameter to identify phase transition points in numerical simulations as the kurtosis of the order parameter. For example in spin glasses one defines the Binder as

${B={\frac {1}{2}}\left(3-{\frac {\overline {\langle q^{4}\rangle }}{{\overline {\langle q^{2}\rangle }}^{2}}}\right)}$

where $\langle \cdot \rangle$ stand for Boltzmann average, ${\overline {\cdot }}$ for average over the disorder and $q$ is the overlap between two identical replicas of the system.