### Non-linear scaling and discount rate adjustments

Targets can be toggled between linear and non-linear tradeoffs by
using the
linear scaling
or
non-linear scaling
icons along the target chart tool bar.

The goal programming formulation uses the difference between the
target and the achieved value as a penalty value. Linear
weights use the difference between target and achievement as is.
Non-linear weights use the square of the difference, thus
greatly favouring values that are further from the target above
those that are close to the target. If the model has a choice
to improve a value that is far away from its target, it will
prefer doing so to improving a value that is already close to
the target.

If you want to 'satisfice' your targets, trying to balance them
all evenly, then use non-linear since this will give an extra
boost to targets that are far below the target. If you want to
get the overall best achievement, without caring how it is
spread through time, then use linear targets.

Non-linear targets seem to work best at getting evenflow
values, or balancing non-equivalent targets (e.g. ecological vs
timber vs budgets). Linear works best for NPV type analysis.

Discount rates can be applied to target values by using the
window on the far right of the toolbar. A default value of 1
implies no discounting. By using the up arrow the discount rate
can be increased by 1% at a time (1.01 = 1% discount rate, 1.03
= 3% discount rate). Likewise, the value can be decreased by
one percent at a time using the down arrow. Use values of less
than 1.0 for compounding.

The discount value will be computed at the mid-point of each
planning period, and then multiplied against the previously set
weighting value. For example, a discount rate of 1.03 will
result in a discount factor of 0.2456 in period 10. This value
will then be multiplied against whatever weight value had
previously been set for the planning period.

Discount rates express an attitude towards risk. When
used with a net value account the effect will be to balance the
stream of benefits to mazimize the discounted value, similar to
a net present value analysis. Compunding rates can be used to
implement targets where the goal is to 'move towards'
achievement over time.