  We calculate the interplanetary magnetic field path lengths traveled by
electrons in solar electron events detected by the WIND 3DP instrument from
$1994$ to $2016$. The velocity dispersion analysis method is applied for
electrons at energies of $\sim$ $27$ keV to $310$ keV. Previous velocity
dispersion analyses employ the onset times, which are often affected by
instrumental effects and the pre-existing background flux, leading to large
uncertainties. We propose a new method here. Instead of using the peak or onset
time, we apply the velocity dispersion analysis to the times that correspond to
the rising phase of the fluxes that are a fraction, $\eta$, of the peak flux.
We perform statistical analysis on selected events whose calculated path
lengths have uncertainties smaller than $0.1$ AU. The mean and standard
deviation, ($\mu$, $\sigma$), of the calculated path lengths corresponding to
$\eta=$ $3/4$, $1/2$, and $1/3$ of the peak flux is ($1.17$ AU, $0.17$ AU),
($1.11$ AU, $0.14$ AU), and ($1.06$ AU, $0.15$ AU). The distribution of the
calculated path lengths is also well fitted by a Gaussian distribution for the
$\eta=3/4$ and $1/3$ cases. These results suggest that in these electron events
the interplanetary magnetic field topology is close to the nominal Parker
spiral with little field line meandering. Our results have important
implications for particles' perpendicular diffusion.
