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Spotfire Ideas Portal
Status Future Consideration
Product Spotfire
Categories Analytics
Created by Guest
Created on Aug 4, 2016

Adding R-Squared to Curve Fits

In Spotfire, on the exponential curve fit and other curve fits, it would be great if the equation displayed would also include the coefficient of determination, or R-Squared value. Not at all different to what Microsoft Excel shows. It would be great to have an option to display or not display it. 

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  • Guest
    Reply
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    Sep 14, 2016

    Calculating R-squared to Evaluate the Fit of Nonlinear Models is not a good practice and might produce wrong outcomes. I think it is not available there for a reason. See this paper for a more deep explanation: 

    An evaluation of R2 as an inadequate measure for nonlinear models in pharmacological and biochemical research: a Monte Carlo approach
    Andrej-Nikolai SpiessEmail author and Natalie Neumeyer

    http://bmcpharma.biomedcentral.com/articles/10.1186/1471-2210-10-6

     

  • Admin
    Tobias Lehtipalo
    Reply
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    Aug 13, 2016

    I assume you know that R2 is calculated for linear fits. You can display it by selecting labels and tooltips for the fit in the lines and curves dialog. However as you point out it is not available for exponential curve fits or any other curve fits besides the linear one.