I think a miss where the earthquake is larger than the prediction is interesting. I don't think a miss on the low end of M2-3 is so interesting. And, for these very small earthquakes you have to worry about detection. There has been some amount of posting on this page of rare California earthquakes (not by Lowell) where the list linked clearly does not have the smaller earthquakes on it, and the one that occurred was smaller than most on the list. You have to also worry about what list is being used-can't have any selection-if there are 3 different magnitudes that are being give you can not select one to best fit the forecast. Chris