Performance of ``Momentum Imbalance" Measurement using the CMS detector at the Large Hadron Collider

With the successful operation of the Large Hadron Collider (LHC) in November and December 2009, the Compact Solenoid Muon (CMS) detector recorded a significant amounts of proton-proton collision data at a center-of-mass energy of 0.9 TeV and 2.36 TeV. The data allow us to understand the detector and prepare a search for dark matter using 7 TeV collisions expected early this year. The creation of dark matter is inferred by measurement of momentum imbalance in each event. The Texas A{\&}M CMS group has been working on the measurement which is very sensitive to the performance of all sub-detector systems in CMS. Thus it is crucial to monitor the data quality. We report the performance of a monitoring program that we have designed and tested with this data.