Hi, Could someone please guide me as to what the threshold factor in the filloutliers represent?

I need to understand if I have a dataset (Data) of (N,M) rows and columns and I use filloutliers to identify the outliers then what does the threshold factor represent in the following script:

filloutliers(Data,'center','median','ThresholdFactor',1.5)

According to mathworks guide the threshold factor is defined as the scaled median absolute deviation, but I need some theoretical background as to what setting 1.5 threshold factor mean? Thanks!