def overall_error_rate(self):
        """Overall error rate metrics (error_rate, substitution_rate, deletion_rate, and insertion_rate)

        Returns
        -------
        dict
            results in a dictionary format

        """

        substitution_rate = metric.substitution_rate(
            Nref=self.overall['Nref'],
            Nsubstitutions=self.overall['Nsubs']
        )

        deletion_rate = metric.deletion_rate(
            Nref=self.overall['Nref'],
            Ndeletions=self.overall['Nfn']
        )

        insertion_rate = metric.insertion_rate(
            Nref=self.overall['Nref'],
            Ninsertions=self.overall['Nfp']
        )

        error_rate = metric.error_rate(
            substitution_rate_value=substitution_rate,
            deletion_rate_value=deletion_rate,
            insertion_rate_value=insertion_rate
        )

        return {
            'error_rate': error_rate,
            'substitution_rate': substitution_rate,
            'deletion_rate': deletion_rate,
            'insertion_rate': insertion_rate
        }