**There are different ways to measure performance. ****We might want to minimize cost/maximize revenue, maximize productivity of people, equipment and facilities, minimize response times and service failures, or meet any of a range of business goals.**

**Uncertainty reveals itself as variability in our ability to meet our goals, and requires designing metrics that capture how we need to manage uncertainty. ****The most popular ways of handling variability include**

**Averages - We want to minimize average costs/maximize average profits****Volatility - We want to minimize the variability in costs, profits and service****Risk - We want to minimize the risk of:****Losses that exceed a planned tolerance****Service failures****Late arrivals**

**Reliability - We may want to maximize the probability that we reach particular goals, either over a period of time, or for specific instances (finishing a project, meeting a sales goal).****Worst-case - What is the smallest safety margin for meeting demand or avoiding accidents?**

**In practice, we often want to balance averages with some measure that captures variability. The right variability measure depends on your setting.**