Todd, there is a scientific article that discussed this but I forget the conclusions (I don't think I read it, I just heard about it). I think it was skeptical. I noticed the quakes before Northridge at the time as unusual and email-discussed it with Lowell Whiteside, who used to post here, and he issued some sort of predicition before Northridge, but I did not see it beforehand, don't remember how specific the prediction was, and don't have the expertise or time to do the statistical analysis to see how signfificant any one prediction is, or a whole bunch of predictions. John V. has posted here about strain transients when there were M4 and 5 quakes on both sides of Baja in the same week (Pacific and Gulf sides), and I don't think it would be too amazing if there was a link in the Santa Monica Bay-Northridge events. Some have been posting here about slow Casacadia events; something like that could modify stresses. Argus et al 2005 JGR model creep on flat faults beneath downtown LA and any change in rate or direction of such creep (if that is the correct model) would change how faults were being loaded.
Again, this needs a John V. comment.
Chris