I could rationalize the message ratio as sort of a self-fulfilling prophecy. If she sent many messages, she was probably already interested in him for some reas

I could rationalize the message ratio as sort of a self-fulfilling prophecy. If she sent many messages, she was probably already interested in him for some reason, and so would be more likely to rate him highly at the end. As a methodological point, I would also have taken the log of all the ratios, especially when doing a linear regression. A ratio of .01 looks like .00001 to a linear regression, but they are quite different. Of course, if the dynamic range is relatively small (probably within 2 fold either direction) maybe it wouldn't matter too much.