Here is a lovely little article in Education Next on school discipline cases arising out of classrooms. The authors are Richard Arum and his doctoral student Doreet Preiss.The article is from a larger essay that is part of this book out from Brookings.
I find their statistics interesting and their presentation sort of cool. I like that they explicitly said they limited their research to only federal and state appellate level cases, even though federal district level cases are also reported for the most part. I liked this statement:
Of course, we did not include the vast majority of litigation, which was either settled before hearing or never reached state and federal appellate courts. Still, our methods provide a way to gauge the general character and broad trends in legal challenges that contemporary educators face. Appellate-level court cases define case law, generate media coverage, influence public perceptions, and can be tracked over time as an empirical indicator of the broad parameters of court climate toward school discipline.
Also, I sort of liked how they broke out the data (just read the article for it) even finding some racial and socio-economic conclusions (although I would fear there is not enough data for too broad of assumptions in this regard).
Anyway, give it a read and think especially about the methodology they used. I think we will see more and more of this type of research in the near future.