Return on Investment (ROI) is the calculation an entity makes in each Turbonomic market cycle to decide what action, if any, it wants to take. ROI equals Revenue divided by Expenses.
For hosts, If ROI is less than 1, the host will remain the same or suspend (after all Virtual Machines move off it). If ROI equals more than 1, the host is considered to be profitable, and might decide to clone itself.
For Virtual Machines (VMs), if ROI equals less than 1, the VM is considered to be unprofitable, and might downsize. If it equals more than 1, the VM is considered to be profitable and might decide to upsize.