def e_score(self, beta=<NUM_LIT:1>):
return <NUM_LIT:1> - self.fbeta_score(beta)<EOL>
r"""Return :math:`E`-score.

        This is Van Rijsbergen's effectiveness measure:
        :math:`E=1-F_{\beta}`.

        Cf. https://en.wikipedia.org/wiki/Information_retrieval#F-measure

        Parameters
        ----------
        beta : float
            The :math:`\beta` parameter in the above formula

        Returns
        -------
        float
            The :math:`E`-score of the confusion table

        Example
        -------
        >>> ct = ConfusionTable(120, 60, 20, 30)
        >>> ct.e_score()
        0.17241379310344818