  Alfv\'enicity is a well-known property, common in the solar wind,
characterized by a high correlation between magnetic and velocity fluctuations.
Data from the Parker Solar Probe (PSP) enable the study of this property closer
to the Sun than ever before, as well as in sub-Alfv\'enic solar wind. We
consider scale-dependent measures of Alfv\'enicity based on second-order
functions of the magnetic and velocity increments as a function of time lag,
including the normalized cross-helicity $\sigma_c$ and residual energy
$\sigma_r$. Scale-dependent Alfv\'enicity is strongest for lags near the
correlation scale and increases when moving closer to the Sun. We find that
$\sigma_r$ typically remains close to the maximally negative value compatible
with $\sigma_c$. We did not observe significant changes in measures of
Alfv\'enicity between sub-Alfv\'enic and super-Alfv\'enic wind. During most
times, the solar wind was highly Alfv\'enic; however, lower Alfv\'enicity was
observed when PSP approached the heliospheric current sheet or other magnetic
structures with sudden changes in the radial magnetic field, non-unidirectional
strahl electron pitch angle distributions, and strong electron density
contrasts. These results are consistent with a picture in which Alfv\'enic
fluctuations generated near the photosphere transport outward forming highly
Alfv\'enic states in the young solar wind and subsequent interactions with
large scale structures and gradients leads to weaker Alfv\'enicity, as commonly
observed at larger heliocentric distances.
