3 Replies Latest reply: Nov 3, 2015 11:39 AM by Gysbert Wassenaar RSS

    Nth degree polynomial trend line support in Qlik Sense 2.1.1?

    Chris Scott

      It appears that via the linest_m and linest_b functions, you can generate a first degree trend line of the form y=mx+b in Qlik Sense, but there does not appear to be any support for generating higher order or nth-degree polynomial lines like there are in QlikView.

       

      Is there a work-around for generating 2nd order trends?

       

      Is there a plan for adding first-class support for n-th degree polynomials?  Even for linear trends it's quite awkward to use linest_m and linest_b to add a simple trend line.

        • Re: Nth degree polynomial trend line support in Qlik?
          Gysbert Wassenaar

          You can add polynomial trendlines using the Trendlines option on the Expressions tab. But there are no functions to manually create such trendlines like you can with the linest_* functions. Considering that Qlik Sense is a BI application and not a Statistics application I don't expect all the exotica of a staticians toolbox to be added. Perhaps someone will find a way to marshal data to and from R in an easy and fast way.

            • Re: Nth degree polynomial trend line support in Qlik?
              Chris Scott

              > You can add polynomial trendlines using the Trendlines option on the Expressions tab.

               

              I should have been more specific in that I was asking about Qlik Sense 2.1.1.  I don't see an expressions tab or an option anywhere to add a trend line and "trendline" doesn't return any hits when I search the documentation.  I would appreciate a pointer if I missed it.

               

              > Considering that Qlik Sense is a BI application and not a Statistics application I don't expect all the exotica of a staticians toolbox to be added. Perhaps someone will find a way to marshal data to and from R in an easy and fast way.

               

              If this functionality is available in QlikView, I would expect it in QlikSense.  This isn't an esoteric function.  This isn't n-variable linear regression where you need matrix operations.  Polynomial trendlines are available in Excel out-of-the-box.  Furthermore, the whole reason for doing trendlines in the first place is to extrapolate out future behavior.

               

              I can't imagine a more basic BI function than "at our current rate of growth, when will we hit $X in sales?".  Growth is almost always accelerating or deaccelerating so a first degree polynomial (e.g. y = mx+b) trendline will almost always be a poor fit for the data.

                • Re: Nth degree polynomial trend line support in Qlik Sense 2.1.1?
                  Gysbert Wassenaar
                  > You can add polynomial trendlines using the Trendlines option on the Expressions tab.

                  Ah, my mistake. That only works in Qlikview. Qlik Sense lacks this functionality at this time.

                   

                  I can't imagine a more basic BI function than "at our current rate of growth, when will we hit $X in sales?". 

                  I can. Count things. The Sumerians began doing this basic BI thing around 3000 BC.

                  In my opinion polynomial equations are not basic BI. Perhaps Excel is a better fit for your BI needs.