During the past few years, sustainability proponents have shown increasing interest in measuring the outcomes of practices as a more direct way to gauge sustainability performance. Measurements used to quantify this performance are called performance metrics. Winegrape growers already use some performance metrics, such as yield per acre and cost of production per acre. Wineries track cases of wine produced, the cost of production per case and numbers of cases sold. However, while these are important, there are many others that could be used as well.