how does listLength exactly works in keda redis ScaledObject?

[revoltez]

in the description it says

listLength: Average target value to trigger scaling actions.

but how is that average value determined? over what period? and can i control the value of that period to have more control?

[zroubalik]

the average there is related to HPA and how does it try to keep this target value in average by scaling in/out pods