The survey covers the period from Oct. 8- Nov. 4, meaning all but 4 days were measured with the new encoders.
Even without a full survey with the new algorithms, their impact on raw average-quarter-hour persons appears to be evident, according to InsideRadio.
Total AQH persons for the Washington, DC metro jumped to 376,800 during the November survey, a 7.2% increase from November 2014.
More significantly, the new number reverses a years-long annual decline in AQH persons.
November’s AQH persons were also up 7.7% when compared to the January-September 2015 average of 349,800.
In Baltimore, the year-over-year increase was far more dramatic, up 26% from 165,200 in Nov. 2014 to 208,100 in Nov. 2015. Like Washington, Baltimore’s November numbers had been slipping prior to 2015. But AQH has been growing in both markets since August 2015.
InsideRadio reports the increases weren’t unexpected. The algorithm updates more effectively hide Nielsen watermarks in a station’s audio signal, allowing it to make PPM codes stronger and more robust while keeping them inaudible. Nielsen field-tested the new CBET on 19 radio stations in various formats in Washington and Baltimore before rolling them out and found that test stations experienced an average 15% increase in AQH persons 6+ with the enhanced encoders.