In statistics and data analysis, the application software SegReg is a free and user-friendly tool for linear segmented regression analysis to determine the breakpoint where the relation between the dependent variable and the independent variable changes abruptly.

To complete the confidence statements, SegReg provides an analysis of variance and an Anova table.

ILRI [4] provides examples of application to magnitudes like crop yield, watertable depth, and soil salinity.

[6] The attached figure concerns the same data as shown in the blue graph in the infobox at the top of this page.

However, the fit of the data beyond the threshold is not as well as in the blue figure that has been made using the principle of minimization of the sum of squares of deviations of the observed values from the regression lines over the whole domain of explanatory variable X (i.e. maximization of the coefficient of determination), while the partial regression is designed only to find the point where the horizontal trend changes into a sloping trend.