Abstract: The performance of oil/and or gas well drilling equipment is measured by: input and output performance sensor assemblies that monitor associated equipment input and output performance characteristics; and alerting an operator if there is an anomaly between the monitored input and output performance characteristics; and wherein furthermore electric or hydraulic power input characteristics supplied to drilling equipment, such as a mud pump, drill string hoist and top drive are compared with delivered output characteristics, such as mud flux, drill string weight and rotation to alert an operator if there is an anomaly between the measured input and output characteristics.