In contrast, the right-hand side of Figure 5 is the predictive
view of costs—the decision support with cost planning
component from Figure 4. Capacity levels and types
of resources can be adjusted in the future. Capacity exists
only as a resource, not as a process or work activity. The
classification of an expense as sunk, fixed, step-fixed,
semivariable, or variable depends on the planning time
horizon. The diagonal line reveals that most expenses
aren’t easily changed in the very short term; hence, they
are classified as fixed. As the time horizon extends into
the future, capacity becomes adjustable. For example,
assets can be leased, not purchased, and future workers
can be contracted from a temporary employment agency,
not hired as full-time employees. Therefore, these
expenses are classified as variable