Comparative applications of simple and complex faculty flow models are examined to determine (1) their relative demands for data and calculations, (2) the divergence of their projections, especially when modelling a no-growth faculty, and (3) an estimate of the error incurred (i.e., the cost to analysis) when a simple model is used. The results support the view that academic personnel policy changes have delayed effects and are nonlinear. It is suggested that simple models may mislead analysts by being insensitive, for example, to backlogs of term appointees who expect promotion. Similarly, it may be that no model is needed at all if one is only looking for estimates on a two-year horizon. (Author/SW)