A model to calculate the analytical sensitivity, limit of detection, limit of determination and precision of a method of instrumental analysis through a data set obtained by calibration experiment using the statistical analysis of linear regression, is proposed. This model has been applied to spectrophotometric, spectrofluorimetric and chromatographic methods. The values obtained are independent of the instrument used and can be applied as a criterion of comparison between different methods proposed for the same analyte. Also, these characteristics have been calculated using the IUPAC suggested model and both results have been compared.