Qlik Community

Qlik Sense App Development

Discussion board where members can learn more about Qlik Sense App Development and Usage.

Not applicable

Nth degree polynomial trend line support in Qlik Sense 2.1.1?

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.

5 Replies

Re: Nth degree polynomial trend line support in Qlik?

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.


talk is cheap, supply exceeds demand
Not applicable

Re: Nth degree polynomial trend line support in Qlik?

> 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?

> 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.


talk is cheap, supply exceeds demand
richbyard
New Contributor III

Re: Nth degree polynomial trend line support in Qlik Sense 2.1.1?

I have been looking at the expressions for trend lines and have documented at Calculating trend lines, values and formulas on charts and tables in Qlik Sense.

However, I have yet to work out the polynomial ones so will be working on this over the next week or so... I'll keep you updated if I manage to solve it...

Re: Nth degree polynomial trend line support in Qlik Sense 2.1.1?

Perhaps using a Vizlib extension that has trendlines built in is an easier solution: Vizlib following the Trend


talk is cheap, supply exceeds demand