A method of controlling a thermodynamic process (20, 50) that includes: - operating the process according to a first operational state for a first period of time (22, 52), - collecting real time operating data for each controllable loss parameter for the process; - calculating individual performance parameters that are relevant for evaluating and controlling the performance of the process; - determining that a sufficient amount of operating data has been collected based on a user-specified number of observations that must be collected over range of loads or based on a specified time period that must elapse to ensure that sufficient data is collected for the process; - performing statistical analysis on the data to determine the achievable performance of the process as a function of the performance parameters, the observed operating data providing distribution curves for the process parameters at the achievable operating conditions; - deriving corrective functions that may be substituted for manufacturer-supplied corrective curves or previously derived correction functions; - determining the achievable performance for the process and the performance parameters to be used for monitoring, evaluating and controlling the real time performance of the device or process versus the achievable performance; - collecting real time data for the current operational state of the monitored process; - calculating and storing performance parameters used to compare the current performance to the achievable performance; - evaluating the amount of data collected and stored by comparing the data collected with a user-specification which is the number of observation that must be collected; - determining that a sufficient amount of operational data has been collected; - calculating a plurality of statistical data for the performance parameters of the monitored process; - evaluating the statistical data by an evaluation of the actual distribution of the performance parameters against a target lower control limit and a target upper control limit, said limits being obtained from the achievable performance previously determined; and - determining a parameter that needs to be adjusted based on the manner in which the actual distribution of the performance parameter diverges from an achievable distribution curve; and - calculating a change to be applied to any of the various parameters of the process by using statistics calculated to determine the change to be applied to the operating parameters; - changing the determined operating parameter of the first operational state to be changed based on the performance parameter statistically achievable value (34, 64). - operating the process according to a first operational state for a first period of time (22, 52), - collecting real time operating data for each controllable loss parameter for the process; - calculating individual performance parameters that are relevant for evaluating and controlling the performance of the process; - determining that a sufficient amount of operating data has been collected based on a user-specified number of observations that must be collected over range of loads or based on a specified time period that must elapse to ensure that sufficient data is collected for the process; - performing statistical analysis on the data to determine the achievable performance of the process as a function of the performance parameters, the observed operating data providing distribution curves for the process parameters at the achievable operating conditions; - deriving corrective functions that may be substituted for manufacturer-supplied corrective curves or previously derived correction functions; - determining the achievable performance for the process and the performance parameters to be used for monitoring, evaluating and controlling the real time performance of the device or process versus the achievable performance; - collecting real time data for the current operational state of the monitored process; - calculating and storing performance parameters used to compare the current performance to the achievable performance; - evaluating the amount of data collected and stored by comparing the data collected with a user-specification which is the number of observation that must be collected; - determining that a sufficient amount of operational data has been collected; - calculating a plurality of statistical data for the performance parameters of the monitored process; - evaluating the statistical data by an evaluation of the actual distribution of the performance parameters against a target lower control limit and a target upper control limit, said limits being obtained from the achievable performance previously determined; and - determining a parameter that needs to be adjusted based on the manner in which the actual distribution of the performance parameter diverges from an achievable distribution curve; and - calculating a change to be applied to any of the various parameters of the process by using statistics calculated to determine the change to be applied to the operating parameters; - changing the determined operating parameter of the first operational state to be changed based on the performance parameter statistically achievable value (34, 64).