Comparison of the model weight pulsation significance, P_m, and the pulsation significance derived when using the pulsar spectrum given by the spectral fit, P_fit, as a function of the “soft–and–flat” estimator S_f for the 131 pulsars with TS >  25 out of the 144 pulsar sample. The eight pulsars with P_m/P_fit >  1.2 are among the pulsars with the largest S_f, meaning those with the softest and flattest spectrum.