The Spectroscopy Net
Gateway to Spectroscopy > Data Acquisition > Calibration > Standard error of estimate:

Standard error of estimate:

The standard error of estimate describes the "average" deviation of a data point from the fitted calibration curve. It is given by the following equation.
  [Standard error of estimate]  
Where n is the number of calibration samples.

And the relative standard error of estimate: These important parameters indicate the accuracy possible near the centre of the calibration curve.

Once the calibration has been done, and before the first analysis, it is time to optimise the calibration curve.

The first step is to choose the order and to select any interfering elements. Generally it is better to use no interference corrections unless these are known and there is an obvious and significant improvement in the statistical parameters.

The BEC should be small and positive. If necessary adjust the weights to achieve this.
If the standard error of estimate is too high, do one or more of the following:

  • increase the number of calibration samples
  • reduce the weight of outliers
  • repeat the calibration with more measurements on each sample
  • reduce the concentration ranges or the number of families of different samples
  • change the calibration function or mode.

Finally the success of the calibration - the order selected, any interference corrections, etc. - should be checked with one or more validation samples, i.e. samples of known composition not included in the calibration.