Significance of ddG

Hello,

We have processed the effect of a missense variant found in a protein of interest to our lab using the STRUM server. The resulting ddG was -1.19. I see from the original paper and from the STRUM server that a mutation resulting in a negative ddG is considered to be destabilizing to the protein. I cannot find any documentation on how to tell if this effect is significant or not (both biologically and/or statistically). How large an effect size is -1.19? Is there a range of ddG that we can reference to tell if this is biologically significant or not? Can STRUM calculate a measure of significance? The majority of my work is in genetics, so I am relatively naiive at protein analysis and modeling.

Thank you for any information you can provide.

Zach W