Methods and assemblies may be used for determining and using standardized spectral responses for calibration of spectroscopic analyzers. The methods and assemblies may be used to calibrate or recalibrate a spectroscopic analyzer when the spectroscopic analyzer changes from a first state to a second state, the second state being defined as a period of time after a change to the spectroscopic analyzer causing a need to calibrate or recalibrate the spectroscopic analyzer. The calibration or recalibration may result in the spectroscopic analyzer outputting a standardized spectrum, such that the spectroscopic analyzer outputs a corrected material spectrum for an analyzed material, and defining the standardized spectrum. The corrected material spectrum may include signals indicative of material properties of an analyzed material, the material properties of the material being substantially consistent with material properties of the material output by the spectroscopic analyzer in the first state.