  The blazar sequence, including negative correlations between radiative
luminosity $L_{\rm rad}$ and synchrotron peak frequency $\nu$, and between
Compton dominance $Y$ and $\nu$, is widely adopted as a phenomenological
description of spectral energy distributions (SEDs) of blazars, although its
underlying cause is hotly debated. In particular, these correlations turn
positive after correcting Doppler boosting effect. In this work, we revisit the
phenomenological and intrinsic blazar sequence with three samples, which are
historical sample (SEDs are built with historical data), quasi-simultaneous
sample (SEDs are built with quasi-simultaneous data) and Doppler factor
corrected sample (a sample with available Doppler factors), selected from
literature. We find that phenomenological blazar sequence holds in historical
sample, but does not exist in quasi-simultaneous sample, and intrinsic
correlation between $L_{\rm rad}$ and $\nu$ becomes positive in Doppler factor
corrected sample. We also analyze if the blazar sequence still exists in
subclasses of blazars, i.e., flat-spectrum radio quasars and BL Lacertae
objects, with different values of $Y$. To interpret these correlations, we
apply a simple scaling model, in which physical parameters of the dissipation
region are connected to the location of the dissipation region. We find that
the model generated results are highly sensitive to the chosen ranges and
distributions of physical parameters. Therefore, we suggest that even though
the simple scaling model can reproduce the blazar sequence under specific
conditions that have been fine-tuned, such results may not have universal
applicability. Further consideration of a more realistic emission model is
expected.
