  For the past 30+ years, the magnetic expansion factor ($f_s$) has been used
in empirical relationships to predict solar wind speed ($v_{obs}$) at 1 AU,
based on an inverse relationship between these two quantities. Coronal unipolar
streamers (i.e. pseudostreamers) undergo limited field line expansion,
resulting in $f_s$-dependent relationships to predict fast wind associated with
these structures. However, case studies have shown that in situ observed
pseudostreamer solar wind was much slower than that derived with $f_s$. To
investigate this further, we conduct a statistical analysis to determine if
$f_s$ and $v_{obs}$ are inversely correlated for a large sample of periods when
pseudostreamer wind was observed at multiple 1 AU spacecraft (i.e. ACE,
STEREO-A/B). We use the Wang-Sheeley-Arge (WSA) model driven by Air Force Data
Assimilative Photospheric Flux Transport (ADAPT) photospheric field maps to
identify 38 periods when spacecraft observe pseudostreamer wind. We compare the
expansion factor of the last open field lines on either side of a
pseudostreamer cusp with the corresponding in situ measured solar wind speed.
We find only slow wind ($v_{obs}$ $<$ 500 km/s) is associated with
pseudostreamers, and that there is not a significant correlation between $f_s$
and $v_{obs}$ for these field lines. This suggests that field lines near the
open-closed boundary of pseudostreamers are not subject to the steady-state
acceleration along continuously open flux tubes assumed in the $f_s$-$v_{obs}$
relationship. In general, dynamics at the boundary between open and closed
field lines such as interchange reconnection will invalidate the steady-state
assumptions of this relationship.
