  The IPPOG and U.S. Particle Physics Masterclasses took place worldwide in
March 2011. For the first time, all masterclasses used real LHC data. Students
in the U.S. Masterclasses (that included participants in several countries
outside the U.S.) analyzed both ATLAS and CMS data. QuarkNet has been
evaluating the U.S. effort since 2008. The design of the LHC masterclasses and
the results of this study will be discussed.
