An application monitoring system determines the health of one or more resources used to process a transaction, business application, or other computer process. Performance data is generated in response to monitoring application execution and processed to determine and an actual and baseline value for resource usage data. Resource usage baseline data may be determined from previous resource usage data associated with a resource and particular transaction (a resource-transaction pair). The baseline values are compared to actual values to determine a deviation for the actual value. Deviation information for the time series data can be reported through an interface or some other manner.