topic Re: Linest() vs Trendline Equation in QlikView

Linest() vs Trendline Equation

matthewjbryant — Wed, 25 Nov 2020 16:16:04 GMT

I'm looking at the Linest() functions and used a Load script found on the Qlik website (attached). The Linest_b() function gives a different value to the intercept value on the trendline equation, but the Linest_b() value appears to be right.

Can anyone tell me what's going on here?

Re: Linest() vs Trendline Equation

Gysbert_Wassenaar — Tue, 03 May 2016 09:28:33 GMT

My guess it that the lineair reference line stops at X=1 and therefore show the value at X=1 as the linest_b value. Whereas your linest expression correctly calculates and show the value for X=0

Re: Linest() vs Trendline Equation

swuehl — Tue, 03 May 2016 09:46:15 GMT

I believe Gysbert is right here.

There are some few threads here that discussed this - non-intuitive IMHO - behaviour of the trendline calculation, e.g.

Matching linest_m and linest_b function to auto-generated trendline

I can only assume that this behaviour was created like it is to show e.g. trendlines for data over time in a more 'natural' way (in a sense that it is only looking at the data points available), since the zero point for dates is quite arbitrarily chosen anyway.