Validation of Data
There's no point in collecting inaccurate data. To get the most accurate information you'll need to tune-up the building systems and check the calibration of sensors and meters. The building systems themselves should be regularly recommissioned or better yet continuously commissioned using a real-time building system analytic tool. Traditional commissioning uses the design documents and design intent for the foundation of commissioning.
Over time however, building spaces or uses may change. So that while you can confirm or validate the design parameters, for example 54° air being delivered by an air handler, the space may have changed and have a different cooling load, not needing 54° air from the air handler. There the systems may need to be adjusted in order to reflect current conditions.
Sensors and meters should be regularly calibrated, including the device itself as well as the communication between the device and its controller. Inaccurate sensors may provide a false sense of complacency and more importantly waste energy and money. For example, assume you have a temperature sensor that is 2°off, showing a discharge air temperature of 55° when it's actually 53°; this two degrees may trigger extra cooling and additional power consumption by the chiller and air handler or reheating of overcooled discharge air which obviously wastes energy.