Out-of-the-box option to add confidence limits to fitted lines on scatter and line charts from Lines and Curves properties dialog page and possibly as a right-click context menu option. Similar in concept to confidence limits already implemented with Holt-Winters forecasting on line charts. Allow user to set the confidence level. (0.95 = default) Here is an example implementation from the STN: http://stn.spotfire.com/stn/Tutorials/HowToAddConfidenceBands.aspx