A complex metric in Optimize is one that is based on other metrics (simple and/or complex). A complex metric is built up in three components: Numerator (N), Denominator (D), and Right Hand Side (RHS). The RHS component itself can be either another metric or a constant value, and can be connected to N/D with one of the four arithmetic signs.

Effectively therefore, a complex metric can take forms such as:

- N/D = straight ratio of two metrics
- N (plus/minus/times/divided by) RHS metric = sum (or difference, product, division) of two metrics
- N (plus/minus/times/divided by) RHS constant = constant applied to a metric
- N/D (plus/minus/times/divided by) RHS metric = sum (or difference, product, division) of a ratio and another metric
- N/D (plus/minus/times/divided by) RHS constant = constant applied to a ratio

Note that not all of these forms lead to valid objective or constraint functions, although such metrics can still be valid for reporting.