Forces that are expected to move against the direction of the historical trend. An example is inventory levels relative to sales: When inventories get too large, holding costs lead managers to reduce their levels, thus opposing the trend. When inventories are too small, service suffers, prompting decisions to hold larger inventories, again, opposing the trend. See Armstrong, Adya and Collopy (2001).

• Armstrong, J. S., M. Adya & F. Collopy (2001), “Rule-based forecasting: Using judgment in time-series  extrapolation,” in J. S. Armstrong (ed.), Principles of Forecasting. Norwell, MA: Kluwer Academic Press.