High quality of Phasor Measurement Unit, PMU, data is vital for power system applications, especially for real time wide area control. PMU data quality can be impacted by filtering and estimation algorithms within PMU, settings and firmware issues, time error, error caused by communication system, data concentrator and data historian. PMU performance testing before installation and remote in-field testing can ensure the data quality at device level. Statistical and data mining approaches supported by physics can be adopted locally at substation level while system level approaches are needed at decentralized and at control center state estimation. This talk will present research activities related to analyzing impact of data quality on PMU applications. A real-time wide area monitoring and control test bed will also be discussed to support the testing and validation of PMUs and PMU based applications. Additionally, development of a tool PMU performance analyzer, PPA, for in lab and remote in-field testing, and data mining approaches for data cleansing will be discussed.