  There has been recent literature discussion on the origin and severity of the
`sign problem' in full configuration interaction quantum Monte Carlo (FCIQMC)
and its `initiator' adaptation (i-FCIQMC), methods of interest and potential
because they allow for exact (FCI) ground-state solutions to be obtained often
at a much reduced computational cost. In this study we aim to use a simple
order parameter, describing the `sign structure' of the stochastic wavefunction
representation, to empirically characterise the fundamentally different
collective behaviour of the walker population in both methods.
