Deviations in P expressed in σ units with respect to Griffin, as a function of the reference period. Systems for which the period, P, in the literature is unlikely to be found (i.e. ∆T < P) are indicated with orange circles. Systems for which ∆T ⩾ P are shown as brown squares. Binaries for which the reference period is not recovered to within 3σ are flagged with green crosses.