Spotfire Ideas Portal
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.
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
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.