Excel 2016 FORECAST.ETS.STAT (Step Size) Meaning?

[johnconnor]

Hi all, I've been googling high and low for the meaning of "step size" in the function FORECAST.ETS.STAT, but I couldn't find anything beyond "Step size detected Returns the step size detected in the historical timeline." What does this mean, actually? This is one of the sources I referred to.

In the sample file provided by microsoft here, under sheet "Forecast.ets sample" cell I76, the "step size" is given as 31 when only (according to my interpretation) 57 period "steps" are selected. The same result (31) shows up even when I choose only 20 periods, from B4 to B20.

Thank you for your help!

 

[AhoyNC]

I think what Excel means by "step size" is if you have seasonal data (say Winter, Spring, Summer, Fall) this would return a step size of 4. If the the pattern was monthly the step size would be 12, etc. Supposedly Excel will detect this from the time line of your data or you can tell it what the step size is.

 

[johnconnor]

Thank you AhoyNC. What do you think about the sample file issue that microsoft provided (the one I mentioned)? Does it make sense for the Step Size to be 31 even when only 20 periods are chosen?

 

[AhoyNC]

In doing a little more research it looks like the step size is "the difference between time values". In their example seasonality = 12, so it looks like Excel is using 31 as the number of days in a month as the step size.