“Relative Accuracy Audit” might be similar to the concept of “Relative Accuracy Test Audit (RATA).” A RATA is a procedure used to assess and verify the accuracy of Continuous Emissions Monitoring Systems (CEMS) by comparing their measurements to reference or standard measurements. This test helps ensure that CEMS provides reliable and accurate data on pollutant emissions from industrial sources. The difference between RAA and RATA is RAA is periodically executed by quarter, while RATA is annually. And the number of runs test is also different between RAA and RATA.